(Slip Opinion)              OCTOBER TERM, 2011                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 

, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

                         WILLIAMS v. ILLINOIS

        CERTIORARI TO THE SUPREME COURT OF ILLINOIS

    No. 10–8505. Argued December 6, 2011—Decided June 18, 2012
At petitioner’s bench trial for rape, Sandra Lambatos, a forensic spe-
  cialist at the Illinois State Police lab, testified that she matched a
  DNA profile produced by an outside laboratory, Cellmark, to a profile
  the state lab produced using a sample of petitioner’s blood. She testi-
  fied that Cellmark was an accredited laboratory and that business
  records showed that vaginal swabs taken from the victim, L. J., were
  sent to Cellmark and returned. She offered no other statement for
  the purpose of identifying the sample used for Cellmark’s profile or
  establishing how Cellmark handled or tested the sample. Nor did
  she vouch for the accuracy of Cellmark’s profile. The defense moved
  to exclude, on Confrontation Clause grounds, Lambatos’ testimony
  insofar as it implicated events at Cellmark, but the prosecution said
  that petitioner’s confrontation rights were satisfied because he had
  the opportunity to cross-examine the expert who had testified as to
  the match. The prosecutor argued that Illinois Rule of Evidence 703
  permitted an expert to disclose facts on which the expert’s opinion is
  based even if the expert is not competent to testify to those underly-
  ing facts, and that any deficiency went to the weight of the evidence,
  not its admissibility. The trial court admitted the evidence and found
  petitioner guilty. Both the Illinois Court of Appeals and the State
  Supreme Court affirmed, concluding that Lambatos’ testimony did
  not violate petitioner’s confrontation rights because Cellmark’s report
  was not offered into evidence to prove the truth of the matter
  asserted.
Held: The judgment is affirmed.

, 

, affirmed.
    JUSTICE ALITO, joined by THE CHIEF JUSTICE, JUSTICE KENNEDY, and
  JUSTICE BREYER, concluded that the form of expert testimony given in
  this case does not violate the Confrontation Clause. Pp. 10–33.
2                         WILLIAMS v. ILLINOIS

                                  Syllabus

       (a) Before Crawford v. Washington, 

, this Court took
    the view that the Confrontation Clause did not bar the admission of
    out-of-court statements that fell within a firmly rooted exception to
    the hearsay rule. In Crawford, the Court held that such statements
    could be “admitted only where the declarant is unavailable, and only
    where the defendant has had a prior opportunity to cross-examine.”
    Id., at 59. In both Melendez-Diaz v. Massachusetts, 

,
    and Bullcoming v. New Mexico, 

___, two of the many cases
    that have arisen from Crawford, this Court ruled that scientific re-
    ports could not be used as substantive evidence against a defendant
    unless the analyst who prepared and certified the report was subject
    to confrontation. In each case, the report at issue “contain[ed] a tes-
    timonial certification, made in order to prove a fact at a criminal
    trial.” 564 U. S., at ___–___. Here, in contrast, the question is the
    constitutionality of allowing an expert witness to discuss others’
    testimonial statements if those statements are not themselves admit-
    ted as evidence. Pp. 10–13.
       (b) An expert witness may voice an opinion based on facts concern-
    ing the events at issue even if the expert lacks first-hand knowledge
    of those facts. A long tradition in American courts permits an expert
    to testify in the form of a “hypothetical question,” where the expert
    assumes the truth of factual predicates and then offers testimony
    based on those assumptions. See Forsyth v. Doolittle, 

,
    77. Modern evidence rules dispense with the need for hypothetical
    questions and permit an expert to base an opinion on facts “made
    known to the expert at or before the hearing,” though such reliance
    does not constitute admissible evidence of the underlying infor-
    mation. Ill. Rule Evid. 703; Fed. Rule Evid. 703. Both Illinois and
    Federal Rules bar an expert from disclosing the inadmissible evi-
    dence in jury trials but not in bench trials. This is important because
    Crawford, while departing from prior Confrontation Clause precedent
    in other respects, reaffirmed the proposition that the Clause “does
    not bar the use of testimonial statements for purposes other than es-
    tablishing the truth of the matter asserted.” 541 U. S., at 59, n. 9.
    Pp. 13–16.
       (c) For Confrontation Clause purposes, the references to Cellmark
    in the trial record either were not hearsay or were not offered for the
    truth of the matter asserted. Pp. 16–27.
          (1) Petitioner’s confrontation right was not violated when Lam-
    batos answered “yes” to a question about whether there was a match
    between the DNA profile “found in semen from the vaginal swabs of
    [L. J.]” and the one identified as petitioner’s. Under Illinois law, this
    putatively offending phrase was not admissible for the purpose of
    proving the truth of the matter asserted—i.e., that the matching
                   Cite as: 567 U. S. ____ (2012)                     3

                              Syllabus

DNA profile was “found in semen from the vaginal swabs.” Rather,
that fact was a mere premise of the prosecutor’s question, and Lam-
batos simply assumed it to be true in giving her answer. Because
this was a bench trial, the Court assumes that the trial judge under-
stood that the testimony was not admissible to prove the truth of the
matter asserted. It is also unlikely that the judge took the testimony
as providing chain-of-custody evidence. The record does not support
such an understanding; no trial judge is likely to be so confused; and
the admissible evidence left little room for argument that Cellmark’s
sample came from any source but L. J.’s swabs, since the profile
matched the very man she identified in a lineup and at trial as her
attacker. Pp. 16–21.
     (2) Nor did the substance of Cellmark’s report need to be intro-
duced in order to show that Cellmark’s profile was based on the se-
men in L. J.’s swabs or that its procedures were reliable. The issue
here is whether petitioner’s confrontation right was violated, not
whether the State offered sufficient foundational evidence to support
the admission of Lambatos’ opinion. If there were no proof that
Cellmark’s profile was accurate, Lambatos’ testimony would be irrel-
evant, but the Confrontation Clause bars not the admission of irrele-
vant evidence, but the admission of testimonial statements by de-
clarants who are not subject to cross-examination. Here, the trial
record does not lack admissible evidence with respect to the source of
the sample tested by Cellmark or the reliability of its profile. The
State offered conventional chain-of-custody evidence, and the match
between Cellmark’s profile and petitioner’s was telling confirmation
that Cellmark’s profile was deduced from the semen on L. J.’s swabs.
The match also provided strong circumstantial evidence about the re-
liability of Cellmark’s work. Pp. 21–25.
     (3) This conclusion is consistent with Bullcoming and Melendez-
Diaz, where forensic reports were introduced for the purpose of prov-
ing the truth of what they asserted. In contrast, Cellmark’s report
was considered for the limited purpose of seeing whether it matched
something else, and the relevance of that match was established by
independent circumstantial evidence showing that the report was
based on a sample from the crime scene. There are at least four safe-
guards to prevent abuses in such situations. First, trial courts can
screen out experts who would act as conduits for hearsay by strictly
enforcing the requirement that experts display genuine “scientific,
technical, or other specialized knowledge” to help the trier of fact un-
derstand the evidence or determine a fact at issue. Fed. Rule Evid.
702(a). Second, experts are generally precluded from disclosing in-
admissible evidence to a jury. Third, if such evidence is disclosed, a
trial judge may instruct the jury that the statements cannot be ac-
4                        WILLIAMS v. ILLINOIS

                                  Syllabus

    cepted for their truth, and that an expert’s opinion is only as good as
    the independent evidence establishing its underlying premises.
    Fourth, if the prosecution cannot muster independent admissible evi-
    dence to prove foundational facts, the expert’s testimony cannot be
    given weight by the trier of fact. Pp. 25–27.
         (e) Even if Cellmark’s report had been introduced for its truth,
    there would have been no Confrontation Clause violation. The
    Clause refers to testimony by “witnesses against” an accused, prohib-
    iting modern-day practices that are tantamount to the abuses that
    gave rise to the confrontation right, namely, (a) out-of-court state-
    ments having the primary purpose of accusing a targeted individual
    of engaging in criminal conduct, and (b) formalized statements such
    as affidavits, depositions, prior testimony, or confessions. These
    characteristics were present in every post-Crawford case in which a
    Confrontation Clause violation has been found, except for Hammon v.
    Indiana, 

. But, even in Hammon, the particular state-
    ment, elicited during police interrogation, had the primary purpose of
    accusing a targeted individual. A person who makes a statement to
    resolve an ongoing emergency is not like a trial witness because the
    declarant’s purpose is to bring an end to an ongoing threat. Michigan
    v. Bryant, 

___, ___. Such a statement’s admissibility “is the
    concern of . . . rules of evidence, not the Confrontation Clause. ” Id.,
    ___–___ . The forensic reports in Melendez-Diaz and Bullcoming ran
    afoul of the Confrontation Clause because they were the equivalent of
    affidavits made for the purpose of proving a particular criminal de-
    fendant’s guilt. But the Cellmark report’s primary purpose was to
    catch a dangerous rapist who was still at large, not to obtain evidence
    for use against petitioner, who was neither in custody nor under sus-
    picion at that time. Nor could anyone at Cellmark possibly know
    that the profile would inculpate petitioner. There was thus no “pro-
    spect of fabrication” and no incentive to produce anything other than
    a scientifically sound and reliable profile. Bryant, supra, at ___, ___.
    Lab technicians producing a DNA profile generally have no way of
    knowing whether it will turn out to be incriminating, exonerating, or
    both. And with numerous technicians working on a profile, it is like-
    ly that each technician’s sole purpose is to perform a task in accord-
    ance with accepted procedures. The knowledge that defects in a DNA
    profile may be detected from the profile itself provides a further safe-
    guard. Pp. 28–33.
       JUSTICE THOMAS concluded that the disclosure of Cellmark’s out-of-
    court statements through Lambatos’ expert testimony did not violate
    the Confrontation Clause solely because Cellmark’s statements
    lacked the requisite “formality and solemnity” to be considered “ ‘tes-
    timonial,’ ” see Michigan v. Bryant, 

___, ___ (THOMAS, J.,
                    Cite as: 567 U. S. ____ (2012)                      5

                               Syllabus

concurring in judgment). Pp. 1–16.
   (a) There was no plausible reason for the introduction of Cellmark’s
statements other than to establish their truth. Pp. 1–8.
     (1) Illinois Rule of Evidence 703 permits an expert to base his
opinion on facts about which he lacks personal knowledge and to dis-
close those facts to the trier of fact. Under Illinois law, such facts are
not admitted for their truth, but only to explain the basis of the ex-
pert’s opinion. See People v. Pasch, 

. But state evi-
dence rules do not trump a defendant’s constitutional right to con-
frontation. This Court ensures that an out-of-court statement was
introduced for a “legitimate, nonhearsay purpose” before relying on
the not-for-its-truth rationale to dismiss the Confrontation Clause’s
application. See Tennessee v. Street, 

, 417. Statements
introduced to explain the basis of an expert’s opinion are not intro-
duced for a plausible nonhearsay purpose because, to use the basis
testimony in evaluating the expert’s opinion, the factfinder must con-
sider the truth of the basis testimony. This commonsense conclusion
is not undermined by any historical practice exempting expert basis
testimony from the rigors of the Confrontation Clause. Before the
Federal Rules of Evidence were adopted in 1975, an expert could ren-
der an opinion based only on facts that the expert had personally per-
ceived or learned at trial. In 1975, that universe of facts was ex-
panded to include facts that the expert learned out of court by means
other than his own perception. The disclosure of such facts raises
Confrontation Clause concerns. Pp. 2–5.
     (2) Those concerns are fully applicable here. In concluding that
petitioner’s DNA profile matched the profile derived from L. J.’s
swabs, Lambatos relied on Cellmark’s out-of-court statements that
its profile was in fact derived from those swabs, rather than from
some other source. Thus, the validity of Lambatos’ opinion ultimate-
ly turned on the truth of Cellmark’s statements. Pp. 5–7.
   (b) These statements, however, were not “testimonial” for purposes
of the Confrontation Clause, which “applies to ‘witnesses’ against the
accused—in other words, those who ‘bear testimony.’ ” Crawford v.
Washington, 

, 51. “ ‘Testimony,’ ” in turn, is “ ‘[a] solemn
declaration or affirmation made for the purpose of establishing or
proving some fact.’ ” Ibid. In light of its text, the Confrontation
Clause regulates only the use of statements bearing “indicia of so-
lemnity.” Davis v. Washington, 

, 836–837, 840 (opinion
of THOMAS, J.). This test comports with history because solemnity
marked the practices that the Confrontation Clause was designed to
eliminate, namely, the ex parte examination of witnesses under Eng-
lish bail and committal statutes. See id., at 835. Accordingly, the
Clause reaches “formalized testimonial materials,” such as deposi-
6                        WILLIAMS v. ILLINOIS

                                  Syllabus

    tions, affidavits, and prior testimony, or statements resulting from
    “formalized dialogue,” such as custodial interrogation. Bryant, supra,
    at ___. Applying these principles, Cellmark’s report is not a state-
    ment by a “witnes[s]” under the Confrontation Clause. It lacks the
    solemnity of an affidavit or deposition, for it is neither a sworn nor a
    certified declaration of fact. And, although it was produced at the re-
    quest of law enforcement, it was not the product of formalized dia-
    logue resembling custodial interrogation. Melendez-Diaz, 

, and Bullcoming v. New Mexico, 

___, distinguished.
    Pp. 8–15.

  ALITO, J., announced the judgment of the Court and delivered an
opinion, in which ROBERTS, C. J., and KENNEDY and BREYER, JJ., joined.
BREYER, J., filed a concurring opinion. THOMAS, J., filed an opinion con-
curring in the judgment. KAGAN, J., filed a dissenting opinion, in which
SCALIA, GINSBURG, and SOTOMAYOR, JJ., joined.
                       Cite as: 567 U. S. ____ (2012)                              1

                             Opinion of ALITO, J.

    NOTICE: This opinion is subject to formal revision before publication in the
    preliminary print of the United States Reports. Readers are requested to
    notify the Reporter of Decisions, Supreme Court of the United States, Wash-
    ington, D. C. 20543, of any typographical or other formal errors, in order
    that corrections may be made before the preliminary print goes to press.


SUPREME COURT OF THE UNITED STATES
                                  _________________

                                  No. 10–8505
                                  _________________


    SANDY WILLIAMS, PETITIONER v. ILLINOIS
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

                                                 

                       ILLINOIS

                               

                                [June 18, 2012] 


   JUSTICE ALITO announced the judgment of the Court
and delivered an opinion, in which THE CHIEF JUSTICE,
JUSTICE KENNEDY, and JUSTICE BREYER join.
   In this case, we decide whether Crawford v. Washing-
ton, 

, 50 (2004), precludes an expert witness
from testifying in a manner that has long been allowed
under the law of evidence. Specifically, does Crawford bar
an expert from expressing an opinion based on facts about
a case that have been made known to the expert but about
which the expert is not competent to testify? We also
decide whether Crawford substantially impedes the ability
of prosecutors to introduce DNA evidence and thus may
effectively relegate the prosecution in some cases to reli-
ance on older, less reliable forms of proof.
   In petitioner’s bench trial for rape, the prosecution
called an expert who testified that a DNA profile produced
by an outside laboratory, Cellmark, matched a profile
produced by the state police lab using a sample of peti-
tioner’s blood. On direct examination, the expert testified
that Cellmark was an accredited laboratory and that
Cellmark provided the police with a DNA profile. The
expert also explained the notations on documents admit-
2                  WILLIAMS v. ILLINOIS

                     Opinion of ALITO, J.

ted as business records, stating that, according to the
records, vaginal swabs taken from the victim were sent to
and received back from Cellmark. The expert made no
other statement that was offered for the purpose of identi-
fying the sample of biological material used in deriving
the profile or for the purpose of establishing how Cellmark
handled or tested the sample. Nor did the expert vouch
for the accuracy of the profile that Cellmark produced.
Nevertheless, petitioner contends that the expert’s testi-
mony violated the Confrontation Clause as interpreted in
Crawford.
   Petitioner’s main argument is that the expert went
astray when she referred to the DNA profile provided by
Cellmark as having been produced from semen found on
the victim’s vaginal swabs. But both the Illinois Appellate
Court and the Illinois Supreme Court found that this
statement was not admitted for the truth of the matter
asserted, and it is settled that the Confrontation Clause
does not bar the admission of such statements. See id., at
59–60, n. 9 (citing Tennessee v. Street, 

(1985)). For more than 200 years, the law of evidence has
permitted the sort of testimony that was given by the ex-
pert in this case. Under settled evidence law, an expert
may express an opinion that is based on facts that the
expert assumes, but does not know, to be true. It is then
up to the party who calls the expert to introduce other
evidence establishing the facts assumed by the expert.
While it was once the practice for an expert who based
an opinion on assumed facts to testify in the form of an an-
swer to a hypothetical question, modern practice does not
demand this formality and, in appropriate cases, permits
an expert to explain the facts on which his or her opinion
is based without testifying to the truth of those facts. See
Fed. Rule Evid. 703. That is precisely what occurred in
this case, and we should not lightly “swee[p] away an
accepted rule governing the admission of scientific evi-
                 Cite as: 567 U. S. ____ (2012)           3

                      Opinion of ALITO, J.

dence.” Melendez-Diaz v. Massachusetts, 

,
330 (2009) (KENNEDY, J., dissenting).
   We now conclude that this form of expert testimony does
not violate the Confrontation Clause because that provi-
sion has no application to out-of-court statements that
are not offered to prove the truth of the matter asserted.
When an expert testifies for the prosecution in a criminal
case, the defendant has the opportunity to cross-examine
the expert about any statements that are offered for their
truth. Out-of-court statements that are related by the
expert solely for the purpose of explaining the assump-
tions on which that opinion rests are not offered for their
truth and thus fall outside the scope of the Confrontation
Clause. Applying this rule to the present case, we con-
clude that the expert’s testimony did not violate the Sixth
Amendment.
   As a second, independent basis for our decision, we also
conclude that even if the report produced by Cellmark had
been admitted into evidence, there would have been no
Confrontation Clause violation. The Cellmark report is
very different from the sort of extrajudicial statements,
such as affidavits, depositions, prior testimony, and con-
fessions, that the Confrontation Clause was originally
understood to reach. The report was produced before any
suspect was identified. The report was sought not for the
purpose of obtaining evidence to be used against petitioner,
who was not even under suspicion at the time, but for
the purpose of finding a rapist who was on the loose. And
the profile that Cellmark provided was not inherently
inculpatory. On the contrary, a DNA profile is evidence
that tends to exculpate all but one of the more than 7
billion people in the world today. The use of DNA evi-
dence to exonerate persons who have been wrongfully
accused or convicted is well known. If DNA profiles could
not be introduced without calling the technicians who
participated in the preparation of the profile, economic
4                  WILLIAMS v. ILLINOIS

                     Opinion of ALITO, J.

pressures would encourage prosecutors to forgo DNA
testing and rely instead on older forms of evidence, such
as eyewitness identification, that are less reliable. See
Perry v. New Hampshire, 565 U. S. ___ (2012). The Con-
frontation Clause does not mandate such an undesirable
development. This conclusion will not prejudice any de-
fendant who really wishes to probe the reliability of the
DNA testing done in a particular case because those who
participated in the testing may always be subpoenaed by
the defense and questioned at trial.
                              I

                              A

  On February 10, 2000, in Chicago, Illinois, a young
woman, L. J., was abducted while she was walking home
from work. The perpetrator forced her into his car and
raped her, then robbed her of her money and other per-
sonal items and pushed her out into the street. L. J. ran
home and reported the attack to her mother, who called
the police. An ambulance took L. J. to the hospital, where
doctors treated her wounds and took a blood sample and
vaginal swabs for a sexual-assault kit. A Chicago Police
detective collected the kit, labeled it with an inventory
number, and sent it under seal to the Illinois State Police
(ISP) lab.
  At the ISP lab, a forensic scientist received the sealed
kit. He conducted a chemical test that confirmed the
presence of semen on the vaginal swabs, and he then
resealed the kit and placed it in a secure evidence freezer.
  During the period in question, the ISP lab often sent
biological samples to Cellmark Diagnostics Laboratory in
Germantown, Maryland, for DNA testing. There was
evidence that the ISP lab sent L. J.’s vaginal swabs to
Cellmark for testing and that Cellmark sent back a report
containing a male DNA profile produced from semen taken
from those swabs. At this time, petitioner was not under
                  Cite as: 567 U. S. ____ (2012)            5

                       Opinion of ALITO, J.

suspicion for L. J.’s rape.
   Sandra Lambatos, a forensic specialist at the ISP lab,
conducted a computer search to see if the Cellmark profile
matched any of the entries in the state DNA database.
The computer showed a match to a profile produced by the
lab from a sample of petitioner’s blood that had been taken
after he was arrested on unrelated charges on August 3,
2000.
   On April 17, 2001, the police conducted a lineup at
which L. J. identified petitioner as her assailant. Peti-
tioner was then indicted for aggravated criminal sexual
assault, aggravated kidnaping, and aggravated robbery.
In lieu of a jury trial, petitioner chose to be tried before a
state judge.
                              B
   Petitioner’s bench trial began in April 2006. In open
court, L. J. again identified petitioner as her attacker.
The State also offered three expert forensic witnesses to
link petitioner to the crime through his DNA. First, Brian
Hapack, an ISP forensic scientist, testified that he had
confirmed the presence of semen on the vaginal swabs
taken from L. J. by performing an acid phosphatase test.
After performing this test, he testified, he resealed the
evidence and left it in a secure freezer at the ISP lab.
   Second, Karen Abbinanti, a state forensic analyst, testi-
fied that she had used Polymerase Chain Reaction (PCR)
and Short Tandem Repeat (STR) techniques to develop a
DNA profile from a blood sample that had been drawn
from petitioner after he was arrested in August 2000. She
also stated that she had entered petitioner’s DNA profile
into the state forensic database.
   Third, the State offered Sandra Lambatos as an expert
witness in forensic biology and forensic DNA analysis. On
direct examination, Lambatos testified about the general
process of using the PCR and STR techniques to generate
6                  WILLIAMS v. ILLINOIS

                     Opinion of ALITO, J.

DNA profiles from forensic samples such as blood and
semen. She then described how these DNA profiles could
be matched to an individual based on the individual’s
unique genetic code. In making a comparison between two
DNA profiles, Lambatos stated, it is a “commonly accepted”
practice within the scientific community for “one DNA
expert to rely on the records of another DNA expert.” App.
51. Lambatos also testified that Cellmark was an “accred-
ited crime lab” and that, in her experience, the ISP lab
routinely sent evidence samples via Federal Express to
Cellmark for DNA testing in order to expedite the testing
process and to “reduce [the lab’s] backlog.” Id., at 49–50.
To keep track of evidence samples and preserve the chain
of custody, Lambatos stated, she and other analysts relied
on sealed shipping containers and labeled shipping mani-
fests, and she added that experts in her field regularly
relied on such protocols. Id., at 50–51.
   Lambatos was shown shipping manifests that were
admitted into evidence as business records, and she ex-
plained what they indicated, namely, that the ISP lab had
sent L. J.’s vaginal swabs to Cellmark, and that Cellmark
had sent them back, along with a deduced male DNA
profile. Id., at 52–55. The prosecutor asked Lambatos
whether there was “a computer match” between “the male
DNA profile found in semen from the vaginal swabs of
[L. J.]” and “[the] male DNA profile that had been identi-
fied” from petitioner’s blood sample. Id., at 55.
   The defense attorney objected to this question for “lack
of foundation,” arguing that the prosecution had offered
“no evidence with regard to any testing that’s been done to
generate a DNA profile by another lab to be testified to by
this witness.” Ibid.
   The prosecutor responded: “I‘m not getting at what
another lab did.” Id., at 56. Rather, she said, she was
simply asking Lambatos about “her own testing based on
[DNA] information” that she had received from Cellmark.
                 Cite as: 567 U. S. ____ (2012)            7

                      Opinion of ALITO, J.

Ibid. The trial judge agreed, noting, “If she says she didn’t
do her own testing and she relied on a test of another lab
and she’s testifying to that, we will see what she’s going to
say.” Ibid.
   The prosecutor then proceeded, asking Lambatos, “Did
you compare the semen that had been identified by Brian
Hapack from the vaginal swabs of [L. J.] to the male DNA
profile that had been identified by Karen [Abbinanti] from
the blood of [petitioner]?” Ibid.
   Lambatos answered “Yes.” Ibid. Defense counsel
lodged an objection “to the form of the question,” but the
trial judge overruled it. Ibid. Lambatos then testified
that, based on her own comparison of the two DNA pro-
files, she “concluded that [petitioner] cannot be excluded
as a possible source of the semen identified in the vaginal
swabs,” and that the probability of the profile’s appearing
in the general population was “1 in 8.7 quadrillion black,
1 in 390 quadrillion white, or 1 in 109 quadrillion Hispanic
unrelated individuals.” Id., at 57. Asked whether she
would “call this a match to [petitioner],” Lambatos an-
swered yes, again over defense counsel’s objection. Id.,
at 58.
   The Cellmark report itself was neither admitted into
evidence nor shown to the factfinder. Lambatos did not
quote or read from the report; nor did she identify it as the
source of any of the opinions she expressed.
   On cross-examination, Lambatos confirmed that she did
not conduct or observe any of the testing on the vaginal
swabs, and that her testimony relied on the DNA profile
produced by Cellmark. Id., at 59. She stated that she
trusted Cellmark to do reliable work because it was an
accredited lab, but she admitted she had not seen any of
the calibrations or work that Cellmark had done in deduc-
ing a male DNA profile from the vaginal swabs. Id., at
59–62.
   Asked whether the DNA sample might have been de-
8                     WILLIAMS v. ILLINOIS

                        Opinion of ALITO, J.

graded before Cellmark analyzed it, Lambatos answered
that, while degradation was technically possible, she
strongly doubted it had occurred in this case. She gave
two reasons. First, the ISP lab likely would have noticed
the degradation before sending the evidence off to Cell-
mark. Second, and more important, Lambatos also noted
that the data making up the DNA profile would ex-
hibit certain telltale signs if it had been deduced from a
degraded sample: The visual representation of the DNA
sequence would exhibit “specific patterns” of degradation,
and she “didn’t see any evidence” of that from looking at
the profile that Cellmark produced. Id., at 81–82.
   When Lambatos finished testifying, the defense moved
to exclude her testimony “with regards to testing done by
[Cellmark]” based on the Confrontation Clause. Id., at 90.
Defense counsel argued that there was “no evidence with
regards to . . . any work done by [Cellmark] to justify
testimony coming into this case with regard to their anal-
ysis.” Ibid. Thus, while defense counsel objected to and
sought the exclusion of Lambatos’ testimony insofar as it
implicated events at the Cellmark lab, defense counsel did
not object to or move for the exclusion of any other portion
of Lambatos’ testimony, including statements regarding
the contents of the shipment sent to or received back from
Cellmark. See id., at 55, 56, 90. See also 

, 367–368, 

, 968 (2008) (chain-of-
custody argument based on shipping manifests waived).
   The prosecution responded that petitioner’s Confronta-
tion Clause rights were satisfied because he had the op-
portunity to cross-examine the expert who had testified
that there was a match between the DNA profiles pro-
duced by Cellmark and Abbinanti. App. 91. Invoking
Illinois Rule of Evidence 703,1 the prosecutor argued that
——————
  1 Consistent with the Federal Rules, Illinois Rule of Evidence 703

provides as follows:
                    Cite as: 567 U. S. ____ (2012)                      9

                          Opinion of ALITO, J.

an expert is allowed to disclose the facts on which the
expert’s opinion is based even if the expert is not compe-
tent to testify to those underlying facts. She further ar-
gued that any deficiency in the foundation for the expert’s
opinion “[d]oesn’t go to the admissibility of [that] testi-
mony,” but instead “goes to the weight of the testimony.”
App. 91.
   The trial judge agreed with the prosecution and stated
that “the issue is . . . what weight do you give the test, not
do you exclude it.” Id., at 94. Accordingly, the judge
stated that he would not exclude Lambatos’ testimony,
which was “based on her own independent testing of the
data received from [Cellmark].” Id., at 94–95 (alteration
in original).
   The trial court found petitioner guilty of the charges
against him. The state court of appeals affirmed in rele-
vant part, concluding that Lambatos’ testimony did not
violate petitioner’s confrontation rights because the Cell-
mark report was not offered into evidence to prove the truth
of the matter it asserted. See 

, at 369,

, at 969–970 (“Cellmark’s report was not
offered for the truth of the matter asserted; rather, it was
offered to provide a basis for Lambatos’ opinion”) The
Supreme Court of Illinois also affirmed. 

,

 (2010). Under state law, the court noted,
the Cellmark report could not be used as substantive
evidence. When Lambatos referenced the report during
her direct examination, she did so “for the limited purpose
of explaining the basis for [her expert opinion],” not for the
purpose of showing “the truth of the matter asserted” by
——————
 “The facts or data in the particular case upon which an expert bases
 an opinion or inference may be those perceived by or made known to
 the expert at or before the hearing. If of a type reasonably relied
 upon by experts in the particular field in forming opinions or inferences
 upon the subject, the facts or data need not be admissible in
 evidence.”
10                  WILLIAMS v. ILLINOIS

                      Opinion of ALITO, J.

the report. Id., at 150, 

, at 282. Thus, the
report was not used to establish its truth, but only “to
show the underlying facts and data Lambatos used before
rendering an expert opinion.” Id., at 145, 

,
at 279.
  We granted certiorari. 

___ (2011).
                              II

                                

                              A

   The Confrontation Clause of the Sixth Amendment
provides that, “[i]n all criminal prosecutions, the accused
shall enjoy the right . . . to be confronted with the wit-
nesses against him.” Before Crawford, this Court took the
view that the Confrontation Clause did not bar the admis-
sion of an out-of-court statement that fell within a firmly
rooted exception to the hearsay rule, see Ohio v. Roberts,

, 66 (1980), but in Crawford, the Court adopted
a fundamentally new interpretation of the confronta-
tion right, holding that “[t]estimonial statements of wit-
nesses absent from trial [can be] admitted only where the
declarant is unavailable, and only where the defendant
has had a prior opportunity to cross-examine.” 541 U. S.,
at 59. Crawford has resulted in a steady stream of new
cases in this Court. See Bullcoming v. New Mexico, 

___ (2011); Michigan v. Bryant, 

___ (2011);
Melendez-Diaz, 

; Giles v. California, 

 (2008); Indiana v. Edwards, 

(2008); Davis v. Washington, 

 (2006).
   Two of these decisions involved scientific reports. In
Melendez-Diaz, the defendant was arrested and charged
with distributing and trafficking in cocaine. At trial, the
prosecution introduced bags of a white powdery substance
that had been found in the defendant’s possession. The
trial court also admitted into evidence three “certificates of
analysis” from the state forensic laboratory stating that
the bags had been “examined with the following results:
                 Cite as: 567 U. S. ____ (2012)           11

                      Opinion of ALITO, J.

The substance was found to contain: Cocaine.” 557 U. S.,
at 308 (internal quotation marks omitted).
   The Court held that the admission of these certificates,
which were executed under oath before a notary, violated
the Sixth Amendment. They were created for “the sole
purpose of providing evidence against a defendant,” id.,
at 323, and were “ ‘quite plainly affidavits,’ ” id., at 330
(THOMAS, J., concurring). The Court emphasized that the
introduction of the report to prove the nature of the sub-
stance found in the defendant’s possession was tanta-
mount to “live, in-court testimony” on that critical fact and
that the certificates did “precisely what a witness does on
direct examination.” Id., at 311 (internal quotation marks
omitted). There was no doubt that the certificates were
used to prove the truth of the matter they asserted. Un-
der state law, “the sole purpose of the affidavits was to
provide prima facie evidence of the composition, quality,
and the net weight of the analyzed substance.” Ibid.
(internal quotation marks omitted and emphasis deleted).
On these facts, the Court said, it was clear that the certif-
icates were “testimonial statements” that could not be
introduced unless their authors were subjected to the “ ‘cru-
cible of cross-examination.’ ” Id., at 311, 317 (quoting
Crawford, supra, at 61).
   In Bullcoming, we held that another scientific report
could not be used as substantive evidence against the de-
fendant unless the analyst who prepared and certified
the report was subject to confrontation. The defendant in
that case had been convicted of driving while intoxicated.
At trial, the court admitted into evidence a forensic report
certifying that a sample of the defendant’s blood had an
alcohol concentration of 0.21 grams per hundred milli-
liters, well above the legal limit. Instead of calling the
analyst who signed and certified the forensic report, the
prosecution called another analyst who had not performed
or observed the actual analysis, but was only familiar with
12                  WILLIAMS v. ILLINOIS

                      Opinion of ALITO, J.

the general testing procedures of the laboratory. The
Court declined to accept this surrogate testimony, despite
the fact that the testifying analyst was a “knowledgeable
representative of the laboratory” who could “explain the
lab’s processes and the details of the report.” 564 U. S., at
___ (KENNEDY, J., dissenting) (slip op., at 1). The Court
stated simply: “The accused’s right is to be confronted with
the analyst who made the certification.” Id., at ___ (slip
op., at 2).
   Just as in Melendez-Diaz, the forensic report that was
“introduce[d]” in Bullcoming “contain[ed] a testimonial
certification, made in order to prove a fact at a criminal
trial.” 564 U. S., at ___–___ (slip op., at 7–8). The report
was signed by the nontestifying analyst who had authored
it, stating, “I certify that I followed the procedures set out
on the reverse of this report, and the statements in this
block are correct. The concentration of alcohol in this
sample is based on the grams of alcohol in one hundred
milliliters of blood.” App. in Bullcoming, O. T. 2010,
No. 09–10876, p. 62. Critically, the report was introduced
at trial for the substantive purpose of proving the truth
of the matter asserted by its out-of-court author—namely,
that the defendant had a blood-alcohol level of 0.21. This
was the central fact in question at the defendant’s trial,
and it was dispositive of his guilt.
   In concurrence, JUSTICE SOTOMAYOR highlighted the im-
portance of the fact that the forensic report had been
admitted into evidence for the purpose of proving the truth
of the matter it asserted. She emphasized that “this [was]
not a case in which an expert witness was asked for his
independent opinion about underlying testimonial reports
that were not themselves admitted into evidence.” 564
U. S., at ___ (slip op., at 6) (opinion concurring in part)
(citing Fed. Rule Evid. 703). “We would face a different
question,” she observed, “if asked to determine the consti-
tutionality of allowing an expert witness to discuss others’
                 Cite as: 567 U. S. ____ (2012)           13

                      Opinion of ALITO, J.

testimonial statements if the testimonial statements were
not themselves admitted as evidence.” Id., at ___ (slip op.,
at 6).
  We now confront that question.
                              B
   It has long been accepted that an expert witness may
voice an opinion based on facts concerning the events at
issue in a particular case even if the expert lacks first-
hand knowledge of those facts.
   At common law, courts developed two ways to deal with
this situation. An expert could rely on facts that had
already been established in the record. But because it was
not always possible to proceed in this manner, and be-
cause record evidence was often disputed, courts devel-
oped the alternative practice of allowing an expert to
testify in the form of a “hypothetical question.” Under this
approach, the expert would be asked to assume the truth
of certain factual predicates, and was then asked to offer
an opinion based on those assumptions. See 1 K. Broun,
McCormick on Evidence §14, p. 87 (6th ed. 2006); 1
J. Wigmore, Evidence §677, p. 1084 (2d ed. 1923) (“If the
witness is skilled enough, his opinion may be adequately
obtained upon hypothetical data alone; and it is immate-
rial whether he has ever seen the person, place or thing in
question” (citation omitted)). The truth of the premises
could then be established through independent evidence,
and the factfinder would regard the expert’s testimony to
be only as credible as the premises on which it was based.
   An early example of this approach comes from the Eng-
lish case of Beckwith v. Sydebotham, 1 Camp. 116, 170
Eng. Rep. 897 (K. B. 1807), where a party sought to prove
the seaworthiness of a ship, the Earl of Wycombe, by
calling as witnesses “several eminent surveyors of ships
who had never seen the ‘Earl of Wycombe.’ ” Ibid. The
opposing party objected to the testimony because it relied
14                  WILLIAMS v. ILLINOIS

                      Opinion of ALITO, J.

on facts that were not known to be true, but the judge
disagreed. Because the experts were “peculiarly ac-
quainted” with “a matter of skill or science,” the judge
said, the “jury might be assisted” by their hypothetical
opinion based on certain assumed facts. Id., at 117, 170 Eng.
Rep., at 897. The judge acknowledged the danger of the
jury’s being unduly prejudiced by wrongly assuming the
truth of the hypothetical facts, but the judge noted that
the experts could be asked on cross-examination what
their opinion of the ship’s seaworthiness would be if differ-
ent hypothetical facts were assumed. If the party that had
called the experts could not independently prove the truth
of the premises they posited, then the experts’ “opinion
might not go for much; but still it was admissible evi-
dence.” Ibid.
   There is a long tradition of the use of hypothetical ques-
tions in American courts. In 1887, for example, this Court
indicated its approval of the following jury instruction:
        “As to the questions, you must understand that they
     are not evidence; they are mere statements to these
     witnesses . . . and, upon the hypothesis or assumption
     of these questions the witnesses are asked to give
     their [opinion]. You must readily see that the value of
     the answers to these questions depends largely, if not
     wholly, upon the fact whether the statements made in
     these questions are sustained by the proof. If the
     statements in these questions are not supported by
     the proof, then the answers to the questions are enti-
     tled to no weight, because based upon false assump-
     tions or statements of facts.” Forsyth v. Doolittle, 

, 77 (internal quotation marks omitted).
  Modern rules of evidence continue to permit experts to
express opinions based on facts about which they lack
personal knowledge, but these rules dispense with the
need for hypothetical questions. Under both the Illinois
                     Cite as: 567 U. S. ____ (2012)                    15

                          Opinion of ALITO, J.

and the Federal Rules of Evidence, an expert may base an
opinion on facts that are “made known to the expert at or
before the hearing,” but such reliance does not constitute
admissible evidence of this underlying information. Ill.
Rule Evid. 703; Fed. Rule Evid. 703. Accordingly, in jury
trials, both Illinois and federal law generally bar an expert
from disclosing such inadmissible evidence.2 In bench
trials, however, both the Illinois and the Federal Rules
place no restriction on the revelation of such information
to the factfinder. When the judge sits as the trier of fact,
it is presumed that the judge will understand the limited
reason for the disclosure of the underlying inadmissible
information and will not rely on that information for any
improper purpose. As we have noted, “[i]n bench trials,
judges routinely hear inadmissible evidence that they are
presumed to ignore when making decisions.” Harris v.
Rivera, 

, 346 (1981) (per curiam). There is a
“well-established presumption” that “the judge [has] ad-
hered to basic rules of procedure,” when the judge is acting
as a factfinder. Id., at 346–347 (emphasis added). See
also Gentile v. State Bar of Nev., 

, 1078
(1991) (Rehnquist, C. J., dissenting).
   This feature of Illinois and federal law is important
because Crawford, while departing from prior Confronta-
tion Clause precedent in other respects, took pains to
reaffirm the proposition that the Confrontation Clause “does
not bar the use of testimonial statements for purposes


——————
  2 But  disclosure of these facts or data to the jury is permitted if the
value of disclosure “substantially outweighs [any] prejudicial effect,”
Fed. Rule Evid. 703, or “the probative value . . . outweighs the risk of
unfair prejudice.” People v. Pasch, 

, 223, 

, 333 (1992). When this disclosure occurs, “the underlying facts” are
revealed to the jury “for the limited purpose of explaining the basis for
[the expert’s] opinion” and not “for the truth of the matter asserted.”
Id., at 176, 

, at 311.
16                 WILLIAMS v. ILLINOIS

                      Opinion of ALITO, J.

other than establishing the truth of the matter asserted.”
541 U. S., at 59–60, n. 9 (citing Tennessee v. Street,

). In Street, the defendant claimed that the
police had coerced him into adopting the confession of his
alleged accomplice. The prosecution sought to rebut this
claim by showing that the defendant’s confession differed
significantly from the accomplice’s. Although the accom-
plice’s confession was clearly a testimonial statement, the
Court held that the jurors could hear it as long as they
were instructed to consider that confession not for its
truth, but only for the “distinctive and limited purpose” of
comparing it to the defendant’s confession, to see whether
the two were identical. Id., at 417.
                             III

                                

                              A

   In order to assess petitioner’s Confrontation Clause
argument, it is helpful to inventory exactly what Lamba-
tos said on the stand about Cellmark. She testified to the
truth of the following matters: Cellmark was an accredited
lab, App. 49; the ISP occasionally sent forensic samples to
Cellmark for DNA testing, ibid.; according to shipping
manifests admitted into evidence, the ISP lab sent vaginal
swabs taken from the victim to Cellmark and later re-
ceived those swabs back from Cellmark, id., at 52–55; and,
finally, the Cellmark DNA profile matched a profile pro-
duced by the ISP lab from a sample of petitioner’s blood,
id., at 55–56. Lambatos had personal knowledge of all
of these matters, and therefore none of this testimony in-
fringed petitioner’s confrontation right.
   Lambatos did not testify to the truth of any other matter
concerning Cellmark. She made no other reference to the
Cellmark report, which was not admitted into evidence
and was not seen by the trier of fact. Nor did she testify to
anything that was done at the Cellmark lab, and she did
not vouch for the quality of Cellmark’s work.
                 Cite as: 567 U. S. ____ (2012) 
        17

                      Opinion of ALITO, J. 


                               B

   The principal argument advanced to show a Confronta-
tion Clause violation concerns the phrase that Lambatos
used when she referred to the DNA profile that the ISP
lab received from Cellmark. This argument is developed
most fully in the dissenting opinion, and therefore we refer
to the dissent’s discussion of this issue.
   In the view of the dissent, the following is the critical
portion of Lambatos’ testimony, with the particular words
that the dissent finds objectionable italicized:

       “Q Was there a computer match generated
       of the male DNA profile found in semen
       from the vaginal swabs of [L.J.] to a male
       DNA profile that had been identified as hav-
       ing originated from Sandy Williams?

       “A Yes, there was.” Post, at 7 (opinion of
       KAGAN, J.) (quoting App. 56; emphasis
       added).

  According to the dissent, the italicized phrase violated
petitioner’s confrontation right because Lambatos lacked
personal knowledge that the profile produced by Cellmark
was based on the vaginal swabs taken from the victim,
L. J. As the dissent acknowledges, there would have been
“nothing wrong with Lambatos’s testifying that two DNA
profiles—the one shown in the Cellmark report and the
one derived from Williams’s blood—matched each other;
that was a straightforward application of Lambatos’s
expertise.” Post, at 12. Thus, if Lambatos’ testimony had
been slightly modified as follows, the dissent would see no
problem:

       “Q Was there a computer match generated
       of the male DNA profile produced by
18                      WILLIAMS v. ILLINOIS

                          Opinion of ALITO, J.

          Cellmark found in semen from the vaginal
          swabs of [L.J.] to a male DNA profile that
          had been identified as having originated
          from Sandy Williams?

          “A Yes, there was.”3

   The defect in this argument is that under Illinois law
(like federal law) it is clear that the putatively offending
phrase in Lambatos’ testimony was not admissible for the
purpose of proving the truth of the matter asserted—i.e.,
that the matching DNA profile was “found in semen from
the vaginal swabs.” Rather, that fact was a mere premise
of the prosecutor’s question, and Lambatos simply as-
sumed that premise to be true when she gave her answer
indicating that there was a match between the two DNA
profiles. There is no reason to think that the trier of fact
took Lambatos’ answer as substantive evidence to estab-
lish where the DNA profiles came from.
   The dissent’s argument would have force if petitioner
had elected to have a jury trial. In that event, there would
have been a danger of the jury’s taking Lambatos’ testi-
mony as proof that the Cellmark profile was derived from
the sample obtained from the victim’s vaginal swabs.
Absent an evaluation of the risk of juror confusion and
careful jury instructions, the testimony could not have
——————
  3 The  small difference between what Lambatos actually said on the
stand and the slightly revised version that the dissent would find un-
objectionable shows that, despite the dissent’s rhetoric, its narrow
argument would have little practical effect in future cases. Prosecutors
would be allowed to do exactly what the prosecution did in this case so
long as their testifying experts’ testimony was slightly modified along
the lines shown above. Following that course presumably would not
constitute a “prosecutorial dodge,” “subterfuge,” “indirection,” the “neat
trick” of “sneak[ing]” in evidence, or the countenancing of constitutional
violations with “a wink and a nod.” See post, at 3, 16, 17, 12 (opinion of
KAGAN, J.).
                     Cite as: 567 U. S. ____ (2012)                  19

                          Opinion of ALITO, J.

gone to the jury.
   This case, however, involves a bench trial and we must
assume that the trial judge understood that the portion of
Lambatos’ testimony to which the dissent objects was not
admissible to prove the truth of the matter asserted.4 The
dissent, on the other hand, reaches the truly remarkable
conclusion that the wording of Lambatos’ testimony con-
fused the trial judge. Were it not for that wording, the
argument goes, the judge might have found that the pros-
ecution failed to introduce sufficient admissible evidence
to show that the Cellmark profile was derived from the
sample taken from the victim, and the judge might have
disregarded the DNA evidence. This argument reflects a
profound lack of respect for the acumen of the trial judge.5
   To begin, the dissent’s argument finds no support in the
trial record. After defense counsel objected to Lambatos’
testimony, the prosecutor made clear that she was asking
Lambatos only about “her own testing based on [DNA]
information” that she had received from Cellmark. App.
56. Recognizing that Lambatos’ testimony would carry
weight only if the underlying premises could be estab-
lished, the judge noted that “the issue is . . . what weight
do you give the test [performed by Lambatos], not do you
exclude it.” Id., at 94. This echoes the old statement in
Beckwith that an expert’s opinion based on disputed prem-
ises “might not go for much; but still it [is] admissible
evidence.” 1 Camp., at 117, 170 Eng. Rep., at 897. Both

——————
  4 We do not suggest that the Confrontation Clause applies differently

depending on the identity of the factfinder. Cf. post, at 14–15 (opinion
of KAGAN, J.). Instead, our point is that the identity of the factfinder
makes a big difference in evaluating the likelihood that the factfinder
mistakenly based its decision on inadmissible evidence.
  5 See post, at 14 (opinion of KAGAN, J.) (“I do not doubt that a judge

typically will do better than a jury in excluding such inadmissible
evidence from his decisionmaking process. Perhaps the judge did so
here” (emphasis added)).
20                     WILLIAMS v. ILLINOIS

                          Opinion of ALITO, J.

the Illinois Appellate Court and the Illinois Supreme
Court viewed the record in this way, and we see no ground
for disagreement.6
   Second, it is extraordinarily unlikely that any trial
judge would be confused in the way that the dissent posits.
That Lambatos was not competent to testify to the chain
of custody of the sample taken from the victim was a point
that any trial judge or attorney would immediately under-
stand. Lambatos, after all, had absolutely nothing to do
with the collection of the sample from the victim, its sub-
sequent handling or preservation by the police in Illinois,
or its shipment to and receipt by Cellmark. No trial judge
would take Lambatos’ testimony as furnishing “the miss-
ing link” in the State’s evidence regarding the identity of
the sample that Cellmark tested. See post, at 6 (opinion of
KAGAN, J.).
   Third, the admissible evidence left little room for argu-
ment that the sample tested by Cellmark came from any
source other than the victim’s vaginal swabs.7 This is so
——————
   6 The dissent finds evidence of the trial judge’s confusion in his

statement that petitioner is “ ‘the guy whose DNA, according to the
evidence from the experts, is in the semen recovered from the victim’s
vagina.’ ” Post, at 14 (emphasis added). The dissent interprets the
phrase “according to the evidence from the experts” as a reference to
what one expert, Lambatos, said about the origin of the sample that
Cellmark tested. In context, however, the judge’s statement is best
understood as attributing to Lambatos nothing more than the conclu-
sion that there was a match between the two DNA profiles that were
compared. The foundational facts, that one of the profiles came from
the defendant and that the other came from “ ‘the semen recovered from
the victim’s vagina,’ ” were established not by expert testimony but by
ordinary chain-of-custody evidence.
   7 Our point is not that admissible evidence regarding the identity of

the sample that Cellmark tested excuses the admission of testimonial
hearsay on this matter. Compare post, at 5–6 (THOMAS, J., concurring
in judgment), with post, at 14 (KAGAN, J., dissenting). Rather, our point
is that, because there was substantial (albeit circumstantial) evidence
on this matter, there is no reason to infer that the trier of fact must
                    Cite as: 567 U. S. ____ (2012)                 21

                         Opinion of ALITO, J.

because there is simply no plausible explanation for how
Cellmark could have produced a DNA profile that matched
Williams’ if Cellmark had tested any sample other than
the one taken from the victim. If any other items that
might have contained Williams’ DNA had been sent
to Cellmark or were otherwise in Cellmark’s possession,
there would have been a chance of a mix-up or of cross-
contamination. See District Attorney’s Office for Third
Judicial Dist. v. Osborne, 

, 80 (2009) (ALITO,
J., concurring). But there is absolutely nothing to suggest
that Cellmark had any such items. Thus, the fact that the
Cellmark profile matched Williams—the very man whom
the victim identified in a lineup and at trial as her at-
tacker—was itself striking confirmation that the sample
that Cellmark tested was the sample taken from the victim’s
vaginal swabs. For these reasons, it is fanciful to suggest
that the trial judge took Lambatos’ testimony as providing
critical chain-of-custody evidence.
                                  C
  Other than the phrase that Lambatos used in referring
to the Cellmark profile, no specific passage in the trial
record has been identified as violating the Confrontation
Clause, but it is nevertheless suggested that the State
somehow introduced “the substance of Cellmark’s report
into evidence.” Post, at 8 (KAGAN, J., dissenting). The
main impetus for this argument appears to be the (errone-
ous) view that unless the substance of the report was
sneaked in, there would be insufficient evidence in the
record on two critical points: first, that the Cellmark
profile was based on the semen in the victim’s vaginal
swabs and, second, that Cellmark’s procedures were reli-
able. This argument is both legally irrelevant for present
purposes and factually incorrect.
—————— 

have taken Lambatos’ statement as providing “the missing link.”

                                                               

22                     WILLIAMS v. ILLINOIS

                          Opinion of ALITO, J.

   As to legal relevance, the question before us is whether
petitioner’s Sixth Amendment confrontation right was
violated, not whether the State offered sufficient founda-
tional evidence to support the admission of Lambatos’
opinion about the DNA match. In order to prove these
underlying facts, the prosecution relied on circumstantial
evidence, and the Illinois courts found that this evidence
was sufficient to satisfy state-law requirements regarding
proof of foundational facts. See 

, at 366–
368, 

, at 967–968; 

, at 138, 

, at 275. We cannot review that interpretation and
application of Illinois law. Thus, even if the record did not
contain any evidence that could rationally support a find-
ing that Cellmark produced a scientifically reliable DNA
profile based on L. J.’s vaginal swab, that would not estab-
lish a Confrontation Clause violation. If there were no
proof that Cellmark produced an accurate profile based on
that sample, Lambatos’ testimony regarding the match
would be irrelevant, but the Confrontation Clause, as
interpreted in Crawford, does not bar the admission of
irrelevant evidence, only testimonial statements by de-
clarants who are not subject to cross-examination.8
   It is not correct, however, that the trial record lacks
admissible evidence with respect to the source of the sam-
ple that Cellmark tested or the reliability of the Cell-
mark profile. As to the source of the sample, the State
offered conventional chain-of-custody evidence, namely,
the testimony of the physician who obtained the vaginal
swabs, the testimony of the police employees who handled
and kept custody of that evidence until it was sent to
——————
  8 Applying the Due Process Clause, we have held that a federal court

may determine whether a rational trier of fact could have found the
existence of all the elements needed for conviction for a state offense.
Jackson v. Virginia, 

, 314 (1979), but petitioner has not
raised a due process claim. And in any event, L. J.’s identification of
petitioner as her assailant would be sufficient to defeat any such claim.
                       Cite as: 567 U. S. ____ (2012)      23

                            Opinion of ALITO, J.

Cellmark, and the shipping manifests, which provided
evidence that the swabs were sent to Cellmark and then
returned to the ISP lab. In addition, as already discussed,
the match between the Cellmark profile and petitioner’s
profile was itself telling confirmation that the Cellmark
profile was deduced from the semen on the vaginal swabs.
   This match also provided strong circumstantial evidence
regarding the reliability of Cellmark’s work. Assuming (for
the reasons discussed above) that the Cellmark profile
was based on the semen on the vaginal swabs, how could
shoddy or dishonest work in the Cellmark lab9 have re-
sulted in the production of a DNA profile that just so
happened to match petitioner’s? If the semen found on the
vaginal swabs was not petitioner’s and thus had an en-
tirely different DNA profile, how could sloppy work in the
Cellmark lab have transformed that entirely different
profile into one that matched petitioner’s? And without
access to any other sample of petitioner’s DNA (and recall
that petitioner was not even under suspicion at this time),
how could a dishonest lab technician have substituted pe-
titioner’s DNA profile? Under the circumstances of this
case, it was surely permissible for the trier of fact to infer
that the odds of any of this were exceedingly low.
   This analysis reveals that much of the dissent’s argu-
ment rests on a very clear error. The dissent argues that
Lambatos’ testimony could be “true” only if the predicate
facts asserted in the Cellmark report were true, and there-
fore Lambatos’ reference to the report must have been
used for the purpose of proving the truth of those facts.
See post, at 10–11. But the truth of Lambatos’ testimony,
properly understood, was not dependent on the truth of
any predicate facts. Lambatos testified that two DNA
profiles matched. The correctness of this expert opinion,
which the defense was able to test on cross-examination,
——————
 9 See   post, at 18 (KAGAN, J., dissenting).
24                      WILLIAMS v. ILLINOIS

                           Opinion of ALITO, J.

was not in any way dependent on the origin of the samples
from which the profiles were derived. Of course, Lamba-
tos’ opinion would have lacked probative value if the pros-
ecution had not introduced other evidence to establish the
provenance of the profiles, but that has nothing to do with
the truth of her testimony.
   The dissent is similarly mistaken in its contention that
the Cellmark report “was offered for its truth because that
is all such ‘basis evidence’ can be offered for.” Post, at 13;
see also post, at 3 (THOMAS, J., concurring in judgment)
(“[S]tatements introduced to explain the basis of an expert’s
opinion are not introduced for a plausible nonhearsay
purpose”). This view is directly contrary to the current
version of Rule 703 of the Federal Rules of Evidence,
which this Court approved and sent to Congress in 2000.
Under that Rule, “basis evidence” that is not admissible
for its truth may be disclosed even in a jury trial under
appropriate circumstances. The purpose for allowing this
disclosure is that it may “assis[t] the jury to evaluate
the expert’s opinion.” Advisory Committee’s 2000 Notes on
Fed. Rule Evid. 703, 

. App., p. 361. The Rule
703 approach, which was controversial when adopted,10 is
based on the idea that the disclosure of basis evidence can
help the factfinder understand the expert’s thought pro-
cess and determine what weight to give to the expert’s
opinion. For example, if the factfinder were to suspect
that the expert relied on factual premises with no support
in the record, or that the expert drew an unwarranted
inference from the premises on which the expert relied,
then the probativeness or credibility of the expert’s opin-
ion would be seriously undermined. The purpose of dis-
closing the facts on which the expert relied is to allay
these fears—to show that the expert’s reasoning was not
illogical, and that the weight of the expert’s opinion does
——————
 10 See   Advisory Committee’s 2000 Notes on Rule 703, at 361.
                  Cite as: 567 U. S. ____ (2012)           25

                       Opinion of ALITO, J.

not depend on factual premises unsupported by other
evidence in the record—not to prove the truth of the un-
derlying facts.
   Perhaps because it cannot seriously dispute the legit-
imate nonhearsay purpose of illuminating the expert’s
thought process, the dissent resorts to the last-ditch ar-
gument that, after all, it really does not matter whether
Lambatos’ statement regarding the source of the Cellmark
report was admitted for its truth. The dissent concedes
that “the trial judge might have ignored Lambatos’s
statement about the Cellmark report,” but nonetheless
maintains that “the admission of that statement violated
the Confrontation Clause even if the judge ultimately put
it aside.” Post, at 15, n. 2. But in a bench trial, it is not
necessary for the judge to stop and make a formal state-
ment on the record regarding the limited reason for which
the testimony is admitted. If the judge does not consider
the testimony for its truth, the effect is precisely the same.
Thus, if the trial judge in this case did not rely on the
statement in question for its truth, there is simply no way
around the proviso in Crawford that the Confrontation
Clause applies only to out-of-court statements that are
“use[d]” to “establis[h] the truth of the matter asserted.”
541 U. S., at 59–60, n. 9 (citing Street, 

).
   For all these reasons, we conclude that petitioner’s Sixth
Amendment confrontation right was not violated.
                            D
  This conclusion is entirely consistent with Bullcoming
and Melendez-Diaz. In those cases, the forensic reports
were introduced into evidence, and there is no question that
this was done for the purpose of proving the truth of what
they asserted: in Bullcoming that the defendant’s blood
alcohol level exceeded the legal limit and in Melendez-
Diaz that the substance in question contained cocaine.
Nothing comparable happened here. In this case, the
26                      WILLIAMS v. ILLINOIS

                           Opinion of ALITO, J.

Cellmark report was not introduced into evidence. An
expert witness referred to the report not to prove the truth
of the matter asserted in the report, i.e., that the report
contained an accurate profile of the perpetrator’s DNA,
but only to establish that the report contained a DNA
profile that matched the DNA profile deduced from peti-
tioner’s blood. Thus, just as in Street, the report was not to
be considered for its truth but only for the “distinctive and
limited purpose” of seeing whether it matched something
else. 471 U. S., at 417. The relevance of the match was
then established by independent circumstantial evidence
showing that the Cellmark report was based on a forensic
sample taken from the scene of the crime.
   Our conclusion will not open the door for the kind of
abuses suggested by some of petitioner’s amici and the
dissent. See post, at 10–11; Brief for Richard D. Friedman
as Amicus Curiae 20–21. In the hypothetical situations
posited, an expert expresses an opinion based on factual
premises not supported by any admissible evidence, and
may also reveal the out-of-court statements on which the
expert relied.11 There are at least four safeguards to
——————
   11 Both JUSTICE THOMAS and JUSTICE KAGAN quote statements in D.

Kaye, D. Bernstein, & J. Mnookin, The New Wigmore: Expert Evidence
§4.10.1, pp. 196–197 (2d ed. 2011) (hereinafter New Wigmore), that are
critical of the theory that an expert, without violating the Confronta-
tion Clause, may express an opinion that is based on testimonial
hearsay and may, in some circumstances, disclose that testimonial
hearsay to the trier of fact. The principal basis for this criticism seems
to be the fear that juries, even if given limiting instructions, will view
the disclosed hearsay as evidence of the truth of the matter asserted.
See id., at 196, n. 36 (referring reader to the more detailed discussion in
Mnookin, Expert Evidence and the Confrontation Clause After Craw-
ford v. Washington, 

. & Pol’y 791 (2007)); New Wigmore 197,
and n. 39 (citing jury cases); Mnookin, supra, at 802–804, 811–813.
This argument plainly has no application in a case like this one, in
which a judge sits as the trier of fact. In the 2012 Supplement of The
New Wigmore, the authors discuss the present case and criticize the
reasoning of the Illinois courts as follows:
                     Cite as: 567 U. S. ____ (2012)                   27

                          Opinion of ALITO, J.

prevent such abuses. First, trial courts can screen out
experts who would act as mere conduits for hearsay by
strictly enforcing the requirement that experts display
some genuine “scientific, technical, or other specialized
knowledge [that] will help the trier of fact to understand
the evidence or to determine a fact in issue.” Fed. Rule
Evid. 702(a). Second, experts are generally precluded
from disclosing inadmissible evidence to a jury. See Fed.
Rule Evid. 703; People v. Pasch, 

, 175–176,

, 310–311 (1992). Third, if such evidence
is disclosed, the trial judges may and, under most circum-
stances, must, instruct the jury that out-of-court state-
ments cannot be accepted for their truth, and that an
expert’s opinion is only as good as the independent evi-
dence that establishes its underlying premises. See Fed.
Rules Evid. 105, 703; People v. Scott, 

, 527–
528, 

, 236–237 (1992). And fourth, if the
prosecution cannot muster any independent admissible
evidence to prove the foundational facts that are essential
to the relevance of the expert’s testimony, then the ex-
pert’s testimony cannot be given any weight by the trier of
fact.12
——————
  “The problem with [the not-for-the-truth-of-the-matter argument
  accepted by the Illinois courts] is that Lambatos had to rely on the
  truth of the statements in the Cellmark report to reach her own con-
  clusion. The claim that evidence that the jury must credit in order to
  credit the conclusion of the expert is introduced for something other
  than its truth is sheer fiction.” New Wigmore §4.11.6, at 24 (2012
  Supp.) (emphasis added).
  This discussion is flawed. It overlooks the fact that there was no jury
in this case, and as we have explained, the trier of fact did not have to
rely on any testimonial hearsay in order to find that Lambatos’ testi-
mony about the DNA match was supported by adequate foundational
evidence and was thus probative.
  12 Our discussion of the first ground for our decision cannot conclude

without commenting on the Kocak case, which dramatically appears at
the beginning of the dissent. In that case, a Cellmark lab analyst
28                      WILLIAMS v. ILLINOIS

                          Opinion of ALITO, J.

                             IV 

                              A

   Even if the Cellmark report had been introduced for its
truth, we would nevertheless conclude that there was no
Confrontation Clause violation. The Confrontation Clause
refers to testimony by “witnesses against” an accused.
Both the noted evidence scholar James Henry Wigmore
and Justice Harlan interpreted the Clause in a strictly
literal sense as referring solely to persons who testify in
court, but we have not adopted this narrow view. It has
been said that “[t]he difficulty with the Wigmore-Harlan
view in its purest form is its tension with much of the
apparent history surrounding the evolution of the right of
confrontation at common law.” White v. Illinois, 

, 360 (1992) (THOMAS, J., concurring). “[T]he principal
evil at which the Confrontation Clause was directed,” the
Court concluded in Crawford, “was the civil-law mode of
criminal procedure, and particularly its use of ex parte
examinations as evidence against the accused.” 541 U. S.,
at 50. “[I]n England, pretrial examinations of suspects
——————
realized while testifying at a pretrial hearing that there was an error in
the lab’s report and that the DNA profile attributed to the accused was
actually that of the victim. The lesson of this cautionary tale is nothing
more than the truism that it is possible for an apparently incriminating
DNA profile to be mistakenly attributed to an accused. But requiring
that the lab analyst or analysts who produced the DNA profile be called
as prosecution witnesses is neither sufficient nor necessary to prevent
such errors. Since samples may be mixed up or contaminated at many
points along the way from a crime scene to the lab, calling one or more
lab analysts will not necessarily catch all such mistakes. For example,
a mistake might be made by a clerical employee responsible for receiv-
ing shipments of samples and then providing them to the lab’s techni-
cians. What is needed is for the trier of fact to make sure that the
evidence, whether direct or circumstantial, rules out the possibility of
such mistakes at every step along the way. And in the usual course of
authentication, defense counsel will have access to sufficient infor-
mation to inquire into, question, or challenge the procedures used by a
laboratory if this seems to be a prudent and productive strategy.
                     Cite as: 567 U. S. ____ (2012)                  29

                          Opinion of ALITO, J.

and witnesses by government officials ‘were sometimes
read in court in lieu of live testimony.’ ” Bryant, 562 U. S.,
at ___ (slip op., at 6) (quoting Crawford, supra, at 43). The
Court has thus interpreted the Confrontation Clause as
prohibiting modern-day practices that are tantamount to
the abuses that gave rise to the recognition of the confron-
tation right. But any further expansion would strain the
constitutional text.
   The abuses that the Court has identified as prompting
the adoption of the Confrontation Clause shared the fol-
lowing two characteristics: (a) they involved out-of-court
statements having the primary purpose of accusing a
targeted individual of engaging in criminal conduct and
(b) they involved formalized statements such as affidavits,
depositions, prior testimony, or confessions. In all but
one of the post-Crawford cases13 in which a Confrontation
Clause violation has been found, both of these characteris-
tics were present. See Bullcoming, 564 U. S., at 308 (slip
op., at 3–4) (certified lab report having purpose of showing
that defendant’s blood-alcohol level exceeded legal limit);
Melendez-Diaz, 557 U. S., at 308 (certified lab report
having purpose of showing that substance connected to
defendant contained cocaine); Crawford, supra, at 38
(custodial statement made after Miranda warnings that
shifted blame from declarant to accused).14 The one excep-
tion occurred in Hammon v. Indiana, 

, 829–
832 (2006), which was decided together with Davis v.
Washington, but in Hammon and every other post-
Crawford case in which the Court has found a violation of
——————
  13 Experience might yet show that the holdings in those cases should

be reconsidered for the reasons, among others, expressed in the dis-
sents the decisions produced. Those decisions are not challenged in this
case and are to be deemed binding precedents, but they can and should
be distinguished on the facts here.
  14 With respect to Crawford, see Davis, 547 U. S., at 840 (THOMAS, J.,

concurring in judgment in part and dissenting in part).
30                  WILLIAMS v. ILLINOIS

                      Opinion of ALITO, J.

the confrontation right, the statement at issue had the
primary purpose of accusing a targeted individual.
                               B
   In Hammon, the one case in which an informal state-
ment was held to violate the Confrontation Clause, we
considered statements elicited in the course of police in-
terrogation. We held that a statement does not fall
within the ambit of the Clause when it is made “under
circumstances objectively indicating that the primary
purpose of the interrogation is to enable police assistance
to meet an ongoing emergency.” 547 U. S., at 822. In
Bryant, another police-interrogation case, we explained
that a person who makes a statement to resolve an ongo-
ing emergency is not acting like a trial witness because
the declarant’s purpose is not to provide a solemn declara-
tion for use at trial, but to bring an end to an ongoing
threat. See 562 U. S., at ___, ___ (slip op., at 11, 14). We
noted that “the prospect of fabrication . . . is presumably
significantly diminished” when a statement is made under
such circumstances, id., at ___ (slip op., at 14) and that
reliability is a salient characteristic of a statement that
falls outside the reach of the Confrontation Clause, id., at
___–___ (slip op., at 14–15). We emphasized that if a
statement is not made for “the primary purpose of creating
an out-of-court substitute for trial testimony,” its admissi-
bility “is the concern of state and federal rules of evidence,
not the Confrontation Clause.” Id., at ___–___ (slip op., at
11–12).
   In Melendez-Diaz and Bullcoming, the Court held that
the particular forensic reports at issue qualified as testi-
monial statements, but the Court did not hold that all
forensic reports fall into the same category. Introduction
of the reports in those cases ran afoul of the Confrontation
Clause because they were the equivalent of affidavits
made for the purpose of proving the guilt of a particular
                  Cite as: 567 U. S. ____ (2012)             31

                       Opinion of ALITO, J.

criminal defendant at trial. There was nothing resembling
an ongoing emergency, as the suspects in both cases had
already been captured, and the tests in question were
relatively simple and can generally be performed by a
single analyst. In addition, the technicians who prepared
the reports must have realized that their contents (which
reported an elevated blood-alcohol level and the presence
of an illegal drug) would be incriminating.
                             C
   The Cellmark report is very different. It plainly was not
prepared for the primary purpose of accusing a targeted
individual. In identifying the primary purpose of an out-
of-court statement, we apply an objective test. Bryant, 562
U. S., at ___ (slip op., at 13). We look for the primary
purpose that a reasonable person would have ascribed to
the statement, taking into account all of the surrounding
circumstances. Ibid.
   Here, the primary purpose of the Cellmark report,
viewed objectively, was not to accuse petitioner or to cre-
ate evidence for use at trial. When the ISP lab sent the
sample to Cellmark, its primary purpose was to catch a
dangerous rapist who was still at large, not to obtain
evidence for use against petitioner, who was neither in
custody nor under suspicion at that time. Similarly, no
one at Cellmark could have possibly known that the
profile that it produced would turn out to inculpate
petitioner—or for that matter, anyone else whose DNA
profile was in a law enforcement database. Under these
circumstances, there was no “prospect of fabrication” and
no incentive to produce anything other than a scientifi-
cally sound and reliable profile. Id., at ___ (slip op., at 14).
   The situation in which the Cellmark technicians found
themselves was by no means unique. When lab techni-
cians are asked to work on the production of a DNA pro-
file, they often have no idea what the consequences of
32                 WILLIAMS v. ILLINOIS

                     Opinion of ALITO, J.

their work will be. In some cases, a DNA profile may
provide powerful incriminating evidence against a person
who is identified either before or after the profile is com-
pleted. But in others, the primary effect of the profile is
to exonerate a suspect who has been charged or is under
investigation. The technicians who prepare a DNA profile
generally have no way of knowing whether it will turn out
to be incriminating or exonerating—or both.
  It is also significant that in many labs, numerous tech-
nicians work on each DNA profile. See Brief for New York
County District Attorney’s Office et al. as Amici Curiae 6
(New York lab uses at least 12 technicians for each case);
People v. Johnson, 

, 627, 

, 79 (2009) (“[A]pproximately 10 Cellmark analysts were
involved in the laboratory work in this case”). When the
work of a lab is divided up in such a way, it is likely that
the sole purpose of each technician is simply to perform
his or her task in accordance with accepted procedures.
  Finally, the knowledge that defects in a DNA profile
may often be detected from the profile itself provides a
further safeguard. In this case, for example, Lambatos
testified that she would have been able to tell from the
profile if the sample used by Cellmark had been degraded
prior to testing. As noted above, moreover, there is no real
chance that “sample contamination, sample switching,
mislabeling, [or] fraud” could have led Cellmark to pro-
duce a DNA profile that falsely matched petitioner. Post,
at 21 (KAGAN, J., dissenting). At the time of the testing,
petitioner had not yet been identified as a suspect, and
there is no suggestion that anyone at Cellmark had a
sample of his DNA to swap in by malice or mistake. And
given the complexity of the DNA molecule, it is inconceiv-
able that shoddy lab work would somehow produce a DNA
profile that just so happened to have the precise genetic
makeup of petitioner, who just so happened to be picked
out of a lineup by the victim. The prospect is beyond
                 Cite as: 567 U. S. ____ (2012)          33

                      Opinion of ALITO, J.

fanciful.
  In short, the use at trial of a DNA report prepared by a
modern, accredited laboratory “bears little if any resem-
blance to the historical practices that the Confrontation
Clause aimed to eliminate.” Bryant, supra, at ___ (slip op.,
at 2) (THOMAS, J., concurring).
                      *     *    *
  For the two independent reasons explained above, we
conclude that there was no Confrontation Clause violation
in this case. Accordingly, the judgment of the Supreme
Court of Illinois is
                                               Affirmed.
                 Cite as: 567 U. S. ____ (2012)          1

                    BREYER, J., concurring

SUPREME COURT OF THE UNITED STATES
                         _________________

                         No. 10–8505
                         _________________


    SANDY WILLIAMS, PETITIONER v. ILLINOIS
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

                                                 

                       ILLINOIS

                               

                        [June 18, 2012] 


  JUSTICE BREYER, concurring.
  This case raises a question that I believe neither the
plurality nor the dissent answers adequately: How does
the Confrontation Clause apply to the panoply of crime
laboratory reports and underlying technical statements
written by (or otherwise made by) laboratory technicians?
In this context, what, if any, are the outer limits of the
“testimonial statements” rule set forth in Crawford v.
Washington, 

 (2004)? Because I believe the
question difficult, important, and not squarely addressed
either today or in our earlier opinions, and because I
believe additional briefing would help us find a proper,
generally applicable answer, I would set this case for
reargument. In the absence of doing so, I adhere to the
dissenting views set forth in Melendez-Diaz v. Massachu-
setts, 

 (2009), and Bullcoming v. New Mexico,

___ (2011). I also join the plurality’s opinion.
                              I

                             A

   This case is another in our series involving the inter-
section of the Confrontation Clause and expert testimony.
Before trial, the prosecution’s expert, Sandra Lambatos,
received a copy of a report prepared by Cellmark Diagnos-
tics Laboratory. That report reflected the fact that
Cellmark technicians had received material from a vaginal
2                  WILLIAMS v. ILLINOIS

                    BREYER, J., concurring

swab taken from the crime victim, had identified semen in
that material, and had derived a profile of the male DNA
that the semen contained. Lambatos then entered that
profile into an Illinois State Police Crime Laboratory
computerized database, which contained, among many
other DNA profiles, a profile derived by the crime labora-
tory from Williams’ blood (taken at an earlier time). The
computer she was using showed that the two profiles
matched. Lambatos then confirmed the match.
   Later, Lambatos testified at trial, where the prosecutor
asked her three relevant questions. First, the prosecutor
asked whether there was “a computer match generated of
the male DNA profile [derived by Cellmark] found in [the]
semen from the vaginal swabs . . . to [the] male DNA
profile [found in the database] that had been identified as
having originated from Sandy Williams”? App. 56. Since
the computer had shown such a match, Lambatos an-
swered affirmatively. Ibid.
   Second, the prosecutor asked whether Lambatos had in-
dependently “compare[d the DNA profile that Cellmark
had derived from] the semen that had been identified . . .
from the vaginal swabs of [the victim] to the male DNA
profile [found in the database] that had been [derived] . . .
from the blood of Sandy Williams.” Ibid. Lambatos again
answered affirmatively. Ibid.
   Third, the prosecutor asked whether, in Lambatos’ ex-
pert opinion, the DNA profile derived from the semen
identified in the vaginal swabs of the victim was “a match
to Sandy Williams.” Id., at 58. Lambatos again answered
affirmatively. Ibid.
   The Confrontation Clause problem lies in the fact that
Lambatos did not have personal knowledge that the male
DNA profile that Cellmark said was derived from the
crime victim’s vaginal swab sample was in fact correctly
derived from that sample. And no Cellmark expert testi-
fied that it was true. Rather, she simply relied for her
                  Cite as: 567 U. S. ____ (2012)             3

                      BREYER, J., concurring

knowledge of the fact upon Cellmark’s report. And the
defendant Williams had no opportunity to cross-examine
the individual or individuals who produced that report.
   In its first conclusion, the plurality explains why it finds
that admission of Lambatos’ testimony nonetheless did not
violate the Confrontation Clause. That Clause concerns
out-of-court statements admitted for their truth. Ante,
at 15–16. Lambatos’ testimony did not introduce the
Cellmark report (which other circumstantial evidence
supported) for its truth. Ante, at 16–21. Rather, Lam-
batos used the Cellmark report only to indicate the under-
lying factual information upon which she based her
independent expert opinion. Ibid. Under well-established
principles of evidence, experts may rely on otherwise
inadmissible out-of-court statements as a basis for forming
an expert opinion if they are of a kind that experts in the
field normally rely upon. See Fed. Rule Evid. 703; Ill.
Rule Evid. 703. Nor need the prosecution enter those out-
of-court statements into evidence for their truth. That,
the Illinois courts held, is just what took place here. Ante,
at 9–10.
   The dissent would abandon this well-established rule.
It would not permit Lambatos to offer an expert opinion
in reliance on the Cellmark report unless the prosecution
also produces one or more experts who wrote or otherwise
produced the report. I am willing to accept the dissent’s
characterization of the present rule as artificial, see post,
at 15–17 (opinion of KAGAN, J.), but I am not certain that
the dissent has produced a workable alternative, see
Bullcoming, supra, at ___ (KENNEDY, J., dissenting) (slip
op., at 7) (expressing similar view).
   Once one abandons the traditional rule, there would
seem often to be no logical stopping place between requir-
ing the prosecution to call as a witness one of the labora-
tory experts who worked on the matter and requiring the
prosecution to call all of the laboratory experts who did so.
4                  WILLIAMS v. ILLINOIS

                    BREYER, J., concurring

Experts—especially laboratory experts—regularly rely on
the technical statements and results of other experts to
form their own opinions. The reality of the matter is that
the introduction of a laboratory report involves layer upon
layer of technical statements (express or implied) made by
one expert and relied upon by another. Hence my general
question: How does the Confrontation Clause apply to
crime laboratory reports and underlying technical state-
ments made by laboratory technicians?
                             B
   The general question is not easy to answer. The Cali-
fornia case described at the outset of the dissenting opin-
ion helps to illustrate the difficulty. In that example,
Cellmark, the very laboratory involved in this case, tested
a DNA sample taken from the crime scene. A laboratory
analyst, relying upon a report the laboratory had prepared,
initially stated (at a pretrial hearing about admissibil-
ity) that the laboratory had found that the crime-scene
DNA sample matched a sample of the defendant’s DNA.
But during the hearing and after reviewing the labor-
atory’s notes, the laboratory analyst realized that the
written report was mistaken. In fact, the testing showed
only that the crime-scene DNA matched a sample of the
victim’s DNA, not the defendant’s DNA. At some point
during the writing of the report, someone, perhaps the
testifying analyst herself, must have misread the proper
original sample labeling. Upon discovering the error, the
analyst corrected her testimony.
   The example is useful, not simply because as adapted
it might show the importance of cross-examination (an
importance no one doubts), but also because it can reveal
the nature of the more general question before us. When
the laboratory in the example received the DNA samples,
it labeled them properly. The laboratory’s final report
mixed up the labels. Any one of many different techni-
                 Cite as: 567 U. S. ____ (2012)            5

                     BREYER, J., concurring

cians could be responsible for an error like that. And the
testifying analyst might not have reviewed the underlying
notes and caught the error during direct examination (or
for that matter, during cross-examination).
   Adapting the example slightly, assume that the admis-
sibility of the initial laboratory report into trial had been
directly at issue. Who should the prosecution have had to
call to testify? Only the analyst who signed the report
noting the match? What if the analyst who made the
match knew nothing about either the laboratory’s underly-
ing procedures or the specific tests run in the particular
case? Should the prosecution then have had to call all
potentially involved laboratory technicians to testify? Six
to twelve or more technicians could have been involved.
(See Appendix, infra, which lists typically relevant labora-
tory procedures.) Some or all of the words spoken or
written by each technician out of court might well have
constituted relevant statements offered for their truth and
reasonably relied on by a supervisor or analyst writing
the laboratory report. Indeed, petitioner’s amici argue
that the technicians at each stage of the process should
be subject to cross-examination. See Brief for Innocence
Network as Amicus Curiae 13–23 (hereinafter Innocence
Network Brief).
   And as is true of many hearsay statements that fall
within any of the 20 or more hearsay exceptions, cross-
examination could sometimes significantly help to elicit
the truth. See Fed. Rule Evid. 803 (listing 24 hearsay
exceptions). The Confrontation Clause as interpreted in
Crawford recognizes, as a limitation upon a pure “testi-
monial statement” requirement, circumstances where the
defendant had an adequate “prior opportunity to cross-
examine.” 541 U. S., at 59. To what extent might the
“testimonial statements” requirement embody one or more
(or modified versions) of these traditional hearsay excep-
tions as well?
6                  WILLIAMS v. ILLINOIS

                    BREYER, J., concurring

   Lower courts and treatise writers have recognized the
problem. And they have come up with a variety of solu-
tions. The New Wigmore, for example, lists several non-
exclusive approaches to when testifying experts may rely
on testing results or reports by nontestifying experts (i.e.,
DNA technicians or analysts), including: (1) “the dominant
approach,” which is simply to determine the need to testify
by looking “the quality of the nontestifying expert’s report,
the testifying expert’s involvement in the process, and the
consequent ability of the testifying expert to use inde-
pendent judgment and interpretive skill”; (2) permitting “a
substitute expert to testify about forensic science results
only when the first expert is unavailable” (irrespective of
the lack of opportunity to cross-examine the first expert,
cf. Crawford, supra, at 59); (3) permitting “a substitute
expert” to testify if “the original test was documented in a
thorough way that permits the substitute expert to evalu-
ate, assess, and interpret it”; (4) permitting a DNA analyst
to introduce DNA test results at trial without having
“personally perform[ed] every specific aspect of each DNA
test in question, provided the analyst was present during
the critical stages of the test, is familiar with the process
and the laboratory protocol involved, reviews the results
in proximity to the test, and either initials or signs the
final report outlining the results”; (5) permitting the in-
troduction of a crime laboratory DNA report without the
testimony of a technician where the “testing in its pre-
liminary stages” only “requires the technician simply to
perform largely mechanical or ministerial tasks . . . absent
some reason to believe there was error or falsification”;
and (6) permitting introduction of the report without
requiring the technicians to testify where there is a show-
ing of “genuine unavailability.” See D. Kaye, D. Bern-
stein, & J. Mnookin, The New Wigmore: Expert Evidence,
§§4.10.2, 4.10.3, pp. 202, 204, 206 (2d ed. 2010) (internal
quotation marks and footnote omitted); id., §4.11.6, at 24
                  Cite as: 567 U. S. ____ (2012)            7

                      BREYER, J., concurring

(Supp. 2012).
   Some of these approaches seem more readily compatible
with Crawford than others. Some seem more easily con-
sidered by a rules committee (or by state courts) than by
this Court. Nonetheless, all assume some kind of Craw-
ford boundary—some kind of limitation upon the scope of
its application—though they reflect different views as to
just how and when that might be done.
   Answering the underlying general question just dis-
cussed, and doing so soon, is important. Trial judges in
both federal and state courts apply and interpret hearsay
rules as part of their daily trial work. The trial of criminal
cases makes up a large portion of that work. And labora-
tory reports frequently constitute a portion of the evidence
in ordinary criminal trials. Obviously, judges, prosecu-
tors, and defense lawyers have to know, in as definitive a
form as possible, what the Constitution requires so that
they can try their cases accordingly.
   The several different opinions filed today embody sev-
eral serious, but different, approaches to the difficult gen-
eral question. Yet none fully deals with the underlying
question as to how, after Crawford, Confrontation Clause
“testimonial statement” requirements apply to crime lab-
oratory reports. Nor can I find a general answer in
Melendez-Diaz or Bullcoming. While, as a matter of pure
logic, one might use those cases to answer a narrowed
version of the question presented here, see post, at 7–8
(KAGAN, J., dissenting), those cases do not fully con-
sider the broader evidentiary problem presented. I conse-
quently find the dissent’s response, “Been there, done
that,” unsatisfactory. See post, at 21.
   Under these circumstances, I would have this case re-
argued. I would request the parties and amici to focus
specifically upon the broader “limits” question. And I
would permit them to discuss, not only the possible impli-
cations of our earlier post-Crawford opinions, but also any
8                  WILLIAMS v. ILLINOIS

                    BREYER, J., concurring

necessary modifications of statements made in the opin-
ions of those earlier cases.
                              II
   In the absence of reargument, I adhere to the dissenting
view set forth in Melendez-Diaz and Bullcoming, under
which the Cellmark report would not be considered “tes-
timonial” and barred by the Confrontation Clause. See
also ante, at 28–33 (setting forth similar conclusion). That
view understands the Confrontation Clause as interpreted
in Crawford to bar the admission of “[t]estimonial” state-
ments made out of court unless the declarant is unavail-
able and the defendant had a prior opportunity to cross-
examine. 541 U. S., at 59 (emphasis added). It also
understands the word “testimonial” as having outer limits
and Crawford as describing a constitutional heartland.
And that view would leave the States with constitutional
leeway to maintain traditional expert testimony rules as
well as hearsay exceptions where there are strong reasons
for doing so and Crawford’s basic rationale does not apply.
   In particular, the States could create an exception that
presumptively would allow introduction of DNA reports
from accredited crime laboratories. The defendant would
remain free to call laboratory technicians as witnesses.
Were there significant reason to question a laboratory’s
technical competence or its neutrality, the presumptive
exception would disappear, thereby requiring the prosecu-
tion to produce any relevant technical witnesses. Such
an exception would lie outside Crawford’s constitutional
limits.
   Consider the report before us. Cellmark’s DNA report
embodies technical or professional data, observations, and
judgments; the employees who contributed to the report’s
findings were professional analysts working on technical
matters at a certified laboratory; and the employees oper-
ated behind a veil of ignorance that likely prevented them
                 Cite as: 567 U. S. ____ (2012)            9

                     BREYER, J., concurring

from knowing the identity of the defendant in this case.
Statements of this kind fall within a hearsay exception
that has constituted an important part of the law of evi-
dence for decades. See Fed. Rule Evid. 803(6) (“Records of
Regularly Conducted Activity”); 2 J. Wigmore, Evidence
§§1517–1533, pp. 1878–1899 (1904) (“Regular Entries”).
And for somewhat similar reasons, I believe that such
statements also presumptively fall outside the category of
“testimonial” statements that the Confrontation Clause
makes inadmissible.
   As the plurality points out, ante, at 28–33, the introduc-
tion of statements of this kind does not risk creating
the “principal evil at which the Confrontation Clause was
directed.” Crawford, 541 U. S., at 50. That evil consists of
the pre-Constitution practice of using “ex parte examina-
tions as evidence against the accused.” Ibid. Sir Walter
Raleigh’s case illustrates the point. State authorities
questioned Lord Cobham, the key witness against Raleigh,
outside his presence. They then used those testimonial
statements in court against Raleigh. And when Raleigh
asked to face and to challenge his accuser, he was denied
that opportunity. See id., at 44.
   The Confrontation Clause prohibits the use of this kind
of evidence because allowing it would deprive a defendant
of the ability to cross-examine the witness. Id., at 61–62;
Mattox v. United States, 

, 242–243 (1895).
That deprivation would prevent a defendant from con-
fronting the witness. And it would thereby prevent a
defendant from probing the witness’ perception, memory,
narration, and sincerity. See, e.g., 2 K. Broun et al.,
McCormick on Evidence §245, p. 125 (6th ed. 2006);
E. Morgan, Some Problems of Proof Under the Anglo-
American System of Litigation 119–127 (1956); 30 C.
Wright & K. Graham, Federal Practice and Procedure
§6324, pp. 44–49 (1997); see also M. Hale, History of the
Common Law of England 258 (1713) (explaining virtues of
10                 WILLIAMS v. ILLINOIS

                     BREYER, J., concurring

confronting witness); 3 W. Blackstone, Commentaries on
the Laws of England 373 (1768) (same). But the need for
cross-examination is considerably diminished when the
out-of-court statement was made by an accredited labora-
tory employee operating at a remove from the investiga-
tion in the ordinary course of professional work.
   For one thing, as the hearsay exception itself reflects,
alternative features of such situations help to guarantee
its accuracy. An accredited laboratory must satisfy well-
established professional guidelines that seek to ensure the
scientific reliability of the laboratory’s results. App. 59–
60, 74, 86–87; see Brief for National District Attorneys
Assn. et al. as Amici Curiae 25, n. 5 (hereinafter NDAA
Brief) (noting that the standards date back 30 years);
Giannelli, Regulating Crime Laboratories: The Impact of
DNA Evidence, 

. & Pol’y 59, 72–76 (2007). For
example, forensic DNA testing laboratories permitted to
access the FBI’s Combined DNA Index System must
adhere to standards governing, among other things, the
organization and management of the laboratory; educa-
tion, training, and experience requirements for laboratory
personnel; the laboratory’s physical facilities and security
measures; control of physical evidence; validation of test-
ing methodologies; procedures for analyzing samples,
including the reagents and controls that are used in the
testing process; equipment calibration and maintenance;
documentation of the process used to test each sample
handled by the laboratory; technical and administrative
review of every case file; proficiency testing of laboratory;
personnel; corrective action that addresses any discrepan-
cies in proficiency tests and casework analysis; internal
and external audits of the laboratory; environmental
health and safety; and outsourcing of testing to vendor
laboratories. See Brief for New York County District
Attorney’s Office et al. as Amici Curiae 4, n. 4 (hereinafter
NY County DAO Brief); see also App. to NY County DAO
                 Cite as: 567 U. S. ____ (2012)          11

                     BREYER, J., concurring

Brief A22–A49.
  These standards are not foolproof. Nor are they always
properly applied. It is not difficult to find instances in
which laboratory procedures have been abused. See, e.g.,
Innocence Network Brief 6–11; App. to Brief for Public
Defender Service for the District of Columbia et al. as
Amici Curiae 1a–12a; cf. Giannelli, The Abuse of Scientific
Evidence in Criminal Cases: The Need for Independent
Crime Laboratories, 4 Va. J. Soc. Pol’y & L. 439 (1997).
Moreover, DNA testing itself has exonerated some defend-
ants who previously had been convicted in part upon the
basis of testimony by laboratory experts. See Melendez-
Diaz v. Massachusetts, 557 U. S., at 319 (citing Garrett &
Neufeld, Invalid Forensic Science Testimony and Wrong-
ful Convictions, 

. Rev. 1 (2009)).
  But if accreditation did not prevent admission of faulty
evidence in some of those cases, neither did cross-
examination. In the wrongful-conviction cases to which
this Court has previously referred, the forensic experts all
testified in court and were available for cross-examination.
Sklansky, Hearsay’s Last Hurrah, 2009 S. Ct. Rev. 1, 72–
73 (cited study “did not identify any cases in which hear-
say from forensic analysts contributed to the conviction of
innocent defendants”); see Garrett & Neufeld, supra, at
10–12, 84, 89 (noting that cross-examination was rarely
effective); see also Murphy, The New Forensics: Criminal
Justice, False Certainty, and the Second Generation of
Scientific Evidence, 

. Rev. 721, 785–786 (2007)
(suggesting need for greater reliance upon accreditation
and oversight of accredited laboratories); Sklansky, supra,
at 74 (same). Similarly, the role of cross-examination is
ambiguous in the laboratory example that the dissent
describes. See post, at 1–2. (Apparently, the report’s error
came to light and was corrected after cross-examination
had concluded, see Thompson, Taroni, & Aitken, Author’s
Response, 49 J. Forensic Sci. 1202 (2003), and in any
12                 WILLIAMS v. ILLINOIS

                    BREYER, J., concurring

event all parties had received the correctly labeled under-
lying laboratory data, see Clarke, Commentary, id., at
1201).
   For another thing, the fact that the laboratory testing
takes place behind a veil of ignorance makes it unlikely
that a particular researcher has a defendant-related mo-
tive to behave dishonestly, say, to misrepresent a step in
an analysis or otherwise to misreport testing results. Cf.
Michigan v. Bryant, 

___, ___ (2011) (slip op., at
14) (discussing the “prospect of fabrication” as a factor in
whether the Confrontation Clause requires statements
“to be subject to the crucible of cross-examination”). The
laboratory here, for example, did not know whether its
test results might help to incriminate a particular defend-
ant. Ante, at 32–33; cf. Melendez-Diaz, supra, at 310–311;
Bullcoming, 564 U. S., at ___ (slip op., at 14).
   Further, the statements at issue, like those of many
laboratory analysts, do not easily fit within the linguistic
scope of the term “testimonial statement” as we have used
that term in our earlier cases. As the plurality notes, in
every post-Crawford case in which the Court has found a
Confrontation Clause violation, the statement at issue had
the primary purpose of accusing a targeted individual.
Ante, at 29–31; see, e.g., Davis v. Washington, 

, 822 (2006) (“primary purpose . . . is to establish or
prove past events potentially relevant to later criminal
prosecution”); Bryant, supra, at ___–___ (slip op., at 11–12)
(“primary purpose of creating an out-of-court substitute
for trial testimony”). The declarant was essentially an
adverse witness making an accusatory, testimonial state-
ment—implicating the core concerns of the Lord Cobham-
type affidavits. But here the DNA report sought, not to
accuse petitioner, but instead to generate objectively a
profile of a then-unknown suspect’s DNA from the semen
he left in committing the crime. See ante, at 31–33.
   Finally, to bar admission of the out-of-court records at
                 Cite as: 567 U. S. ____ (2012)          13

                     BREYER, J., concurring

issue here could undermine, not fortify, the accuracy of
factfinding at a criminal trial. Such a precedent could
bar the admission of other reliable case-specific technical
information such as, say, autopsy reports. Autopsies, like
the DNA report in this case, are often conducted when it is
not yet clear whether there is a particular suspect or
whether the facts found in the autopsy will ultimately
prove relevant in a criminal trial. Autopsies are typically
conducted soon after death. And when, say, a victim’s
body has decomposed, repetition of the autopsy may not be
possible. What is to happen if the medical examiner dies
before trial? E.g., State v. Lackey, 

, 195–196,

, 341 (2005); see also People v. Geier, 

 555, 601–602, 

, 136–137 (2007). Is the
Confrontation Clause “ ‘effectively’ ” to function “ ‘as a
statute of limitations for murder’ ”? Melendez-Diaz, supra,
at 335 (KENNEDY, J., dissenting) (quoting Comment, To-
ward a Definition of “Testimonial”: How Autopsy Reports
Do Not Embody the Qualities of a Testimonial Statement,

. Rev. 1093, 1115 (2008)).
  In general, such a holding could also increase the risk of
convicting the innocent. The New York County District
Attorney’s Office and the New York City Office of the
Chief Medical Examiner tell us that the additional cost
and complexity involved in requiring live testimony from
perhaps dozens of ordinary laboratory technicians who
participate in the preparation of a DNA profile may well
force a laboratory “to reduce the amount of DNA testing it
conducts, and force prosecutors to forgo forensic DNA
analysis in cases where it might be highly probative. In
the absence of DNA testing, defendants might well be
prosecuted solely on the basis of eyewitness testimony, the
reliability of which is often questioned.” NY County DAO
Brief 10 (citing United States v. Wade, 

, 229
(1967)); see also NDAA Brief 26 (such a holding “will also
impact the innocent who may wait to be cleared from
14                 WILLIAMS v. ILLINOIS

                    BREYER, J., concurring

suspicion or exonerated from mistaken conviction”). I find
this plausible. But cf. Innocence Network Brief 3. An
interpretation of the Clause that risks greater prosecution
reliance upon less reliable evidence cannot be sound. Cf.
Maryland v. Craig, 

, 845 (1990) (“The central
concern of the Confrontation Clause is to ensure the reli-
ability of the evidence against a criminal defendant”).
   Consequently, I would consider reports such as the DNA
report before us presumptively to lie outside the perimeter
of the Clause as established by the Court’s precedents.
Such a holding leaves the defendant free to call the labora-
tory employee as a witness if the employee is available.
Moreover, should the defendant provide good reason to
doubt the laboratory’s competence or the validity of its
accreditation, then the alternative safeguard of reliability
would no longer exist and the Constitution would entitle
defendant to Confrontation Clause protection. Similarly,
should the defendant demonstrate the existence of a mo-
tive to falsify, then the alternative safeguard of honesty
would no longer exist and the Constitution would entitle
the defendant to Confrontation Clause protection. Cf. 2
Wigmore, Evidence §1527, at 1892 (in respect to the busi-
ness records exception, “there must have been no motive
to misrepresent”). Thus, the defendant would remain free
to show the absence or inadequacy of the alternative
reliability/honesty safeguards, thereby rebutting the pre-
sumption and making the Confrontation Clause applicable.
No one has suggested any such problem in respect to
the Cellmark Report at issue here.
   Because the plurality’s opinion is basically consistent
with the views set forth here, I join that opinion in full.
                 Cite as: 567 U. S. ____ (2012)           15

                     BREYER, J., concurring
                Appendix to opinion of BREYER, J.

                        APPENDIX
   This appendix outlines the way that a typical modern fo-
rensic laboratory conducts DNA analysis. See NY County
DAO Brief 7–8; NDAA Brief 22–23; Innocence Network
Brief 13–23; see also Dept. of Justice, Office of the Inspec-
tor General, The FBI DNA Laboratory: A Review of Proto-
col and Practice Vulnerabilities 6–14 (May 2004), online at
http://www.justice.gov/oig/special/0405/final.pdf (as visited
June 14, 2012, and available in Clerk of Court’s case file).
The DNA analysis takes place in three parts, through
three different sets of laboratory experts: (1) a DNA pro-
file is derived from the suspect’s DNA sample, (2) a DNA
profile is derived from the crime-scene DNA sample, and
(3) an analyst compares the two profiles and makes a
conclusion.
   As many as six technicians may be involved in deriving
the profile from the suspect’s sample; as many as six more
technicians may be involved in deriving the profile from
the crime-scene sample; and an additional expert may
then be required for the comparative analysis, for a total
of about a dozen different laboratory experts. Each expert
may make technical statements (express or implied) dur-
ing the DNA analysis process that are in turn relied upon
by other experts. The amici dispute how many of these
experts the Confrontation Clause requires to be subject to
cross-examination. Compare Innocence Network Brief 13–
23 with NY County DAO Brief 7–8 and NDAA Brief 22–
23. In charting the three-step process, the appendix first
summarizes the laboratory procedures used to derive a
DNA profile and then illustrates potential statements that
technicians may make to explain their analysis.
16                   WILLIAMS v. ILLINOIS 


                     BREYER, J., concurring
                 Appendix to opinion of BREYER, J. 


A. Profile of Suspect’s Sample (Summary of Lab Process)
      1. Technician #1:                     2. Technician #2:
  Evidence Examination                          Extraction
 Forensics lab receives                  Tech #2 extracts DNA
 crime-scene evidence.                   from cuttings or swab-
 Tech #1 examines the                    bings, i.e., adds chemi-
 evidence for biological                 cal reagents to the
 fluids/materials and tests              sample that break open
 whether the results reveal              the cells and free up the
 the presence of a biological            DNA so that it is acces-
 sample. If present, Tech                sible for testing.
 #1 takes cuttings or
 swabbings from evidence
 for DNA extraction.
                                            3. Technician #3:
                                             Quantification
      4. Technician #4:                  Tech #3 measures the
        Amplification                    amount of DNA that is
 Tech #4 amplifies (copies)              present in the sample to
 the extracted DNA using                 ensure that there is
 polymerase chain reaction               enough DNA for testing.
 (PCR), i.e., uses a highly
 automated process to tar-
 get, tag, and copy specific                   6. Technicians
 locations (loci), raising                  #5 and #6: Report
 them to a detectable level.               Techs #5 and #6 use
                                           software to determine
                                           allele calls (i.e.,
                                           length) and produce a
     5. Technicians #5 and #6:             report. The software
          Electrophoresis                  measures the length
                                           of the DNA fragments
                                           produced by electro-
                                           phoresis, determines
                                           the alleles that corre-
                                           spond to the frag-
                                           ments, and compiles a
                                           DNA profile for the
                                           sample. The Techs
                                           record what the allele
                                           values are at each loci
                                           analyzed, which, once
                                           compiled, constitute a
                                           DNA profile.
                  Cite as: 567 U. S. ____ (2012) 
               17

                     BREYER, J., concurring
                Appendix to opinion of BREYER, J. 


B. Profile of Crime-Scene Sample (Examples of Statements)
      7. Technician #7:                     8. Technician #8:
  Evidence Examination                          Extraction
 “The crime-scene evidence              “I used the proper
 was submitted in a proper-             procedures and added
 ly sealed packaged, and I              the proper chemical
 unpackaged it using the                reagents to the sample
 proper precautions to                  to break open the cells
 ensure contamination did               to free up the DNA so
 not occur. Using the                   that it became accessi-
 proper tests, I determined             ble for further testing. I
 that DNA suitable for                  followed the proper
 testing was present in the             precautions to ensure
 evidence. I used the proper            contamination did not
 procedures to take cuttings            occur. The procedures I
 or swabbings from the                  followed are generally
 evidence and to preserve               accepted in the scien-
 them for further testing.              tific community.”
 The procedures I followed
 are generally accepted in
 the scientific community.”
                                            9. Technician #9:
                                             Quantification
     10. Technician #10:                “I conducted a proper
        Amplification                   PCR process, placing
 “Using the proper proce-               the sample in the prop-
 dures, I used the proper               er equipment, running
 chemicals to measure the               the proper number of
 amount of DNA in the                   cycles, and using the
 sample accurately and to               proper chemical rea-
 normalize the sample to the            gents to trigger the
 proper concentration. The              reactions that copy the
 procedures I followed are              DNA. I followed the
 generally accepted in the              proper precautions to
 scientific community.”                 guard against contami-
                                        nation. The procedures
                                        I followed are generally
                                        accepted in the scientific
        (Continued)
                                        community.”
18                  WILLIAMS v. ILLINOIS

                    BREYER, J., concurring
                Appendix to opinion of BREYER, J.

        (Continued)



                                             12. Technicians
       Electrophoresis                    #11 and #12: Report
 “We conducted a proper                  “Using the proper
 electrophoresis, using the              computer software, we
 proper procedures to place              properly transcribed
 the DNA in the properly                 the data produced by
 calibrated equipment run in             the electropherogram
 the proper conditions. We               into a report. We
 followed the proper precau-             applied the proper
 tions to avoid cross-sample             criteria to review the
 contamination. The proce-               computer determina-
 dures we followed used are              tions of what the allele
 generally accepted in the               values are at each of
 scientific community.”                  the chromosomal
                                         locations analyzed.
                                         We properly docu-
                                         mented those allele
                                         values to produce the
                                         DNA profile. The
                                         procedures we fol-
                                         lowed are generally
                                         accepted in the scien-
                                         tific community.”



C. Comparison Between the Two DNA Profiles

                          13. Analyst
 Analyst (who eventually testifies in court) compares the two
 electropherograms and reports, i.e., compares the elec-
 tropherograms and profiles from the crime-scene DNA to the
 defendant’s DNA. Analyst then prepares her own report
 setting forth her conclusions about the DNA match.
                 Cite as: 567 U. S. ____ (2012)           1

               THOMAS, J., concurring in judgment

SUPREME COURT OF THE UNITED STATES
                          _________________

                          No. 10–8505
                          _________________


     SANDY WILLIAMS, PETITIONER v. ILLINOIS
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

                                                 

                       ILLINOIS

                               

                        [June 18, 2012] 


  JUSTICE THOMAS, concurring in the judgment.
  I agree with the plurality that the disclosure of
Cellmark’s out-of-court statements through the expert
testimony of Sandra Lambatos did not violate the Con-
frontation Clause. I reach this conclusion, however, solely
because Cellmark’s statements lacked the requisite “for-
mality and solemnity” to be considered “ ‘testimonial’ ” for
purposes of the Confrontation Clause. See Michigan v.
Bryant, 

___, ___ (2011) (THOMAS, J., concurring
in judgment) (slip op., at 1). As I explain below, I share
the dissent’s view of the plurality’s flawed analysis.
                              I
   The threshold question in this case is whether Cell-
mark’s statements were hearsay at all. As the Court
has explained, “[t]he [Confrontation] Clause . . . does not
bar the use of testimonial statements for purposes other
than establishing the truth of the matter asserted.” See
Crawford v. Washington, 

, 60, n. 9 (2004)
(citing Tennessee v. Street, 

, 414 (1985)).
Here, the State of Illinois contends that Cellmark’s state-
ments—that it successfully derived a male DNA profile
and that the profile came from L. J.’s swabs—were intro-
duced only to show the basis of Lambatos’ opinion, and not
for their truth. In my view, however, there was no plau-
sible reason for the introduction of Cellmark’s statements
2                   WILLIAMS v. ILLINOIS

               THOMAS, J., concurring in judgment

other than to establish their truth.
                               A
   Illinois Rule of Evidence 703 (2011) and its federal
counterpart permit an expert to base his opinion on facts
about which he lacks personal knowledge and to disclose
those facts to the trier of fact. Relying on these Rules, the
State contends that the facts on which an expert’s opinion
relies are not to be considered for their truth, but only to
explain the basis of his opinion. See People v. Pasch, 

, 176, 

, 311 (1992) (“By allowing
an expert to reveal the information for this purpose alone,
it will undoubtedly aid the jury in assessing the value of
his opinion”); see also Advisory Committee’s Notes on Fed.
Rule Evid. 703, 

. App., p. 361 (stating that ex-
pert basis testimony is admissible “only for the purpose
of assisting the jury in evaluating an expert’s opinion”).
Accordingly, in the State’s view, the disclosure of expert
“basis testimony” does not implicate the Confrontation
Clause.
   I do not think that rules of evidence should so easily
trump a defendant’s confrontation right. To be sure, we
should not “lightly swee[p] away an accepted rule” of
federal or state evidence law, ante, at 2 (internal quotation
marks omitted), when applying the Confrontation Clause.
“Rules of limited admissibility are commonplace in evi-
dence law.” Mnookin, Expert Evidence and the Confronta-
tion Clause after Crawford v. Washington, 

. & Pol’y
791, 812 (2007). And, we often presume that courts and
juries follow limiting instructions. See, e.g., Street, supra,
at 415, n. 6. But we have recognized that concepts central
to the application of the Confrontation Clause are ulti-
mately matters of federal constitutional law that are not
dictated by state or federal evidentiary rules. See Barber
v. Page, 

, 724–725 (1968) (defining a consti-
tutional standard for whether a witness is “unavailable”
                 Cite as: 567 U. S. ____ (2012)            3

               THOMAS, J., concurring in judgment

for purposes of the Confrontation Clause); see also Ohio v.
Roberts, 

, 76 (1980) (recognizing that Barber
“explored the issue of constitutional unavailability” (em-
phasis added)). Likewise, we have held that limiting in-
structions may be insufficient in some circumstances to
protect against violations of the Confrontation Clause.
See Bruton v. United States, 

 (1968).
   Of particular importance here, we have made sure that
an out-of-court statement was introduced for a “legitimate,
nonhearsay purpose” before relying on the not-for-its-truth
rationale to dismiss the application of the Confrontation
Clause. See Street, 471 U. S., at 417 (emphasis added). In
Street, the defendant testified that he gave a false confes-
sion because police coerced him into parroting his accom-
plice’s confession. Id., at 411. On rebuttal, the prosecu-
tion introduced the accomplice’s confession to demonstrate
to the jury the ways in which the two confessions differed.
Id., at 411–412. Finding no Confrontation Clause prob-
lem, this Court held that the accomplice’s out-of-court
confession was not introduced for its truth, but only to
impeach the defendant’s version of events. Id., at 413–
414. Although the Court noted that the confession was
not hearsay “under traditional rules of evidence,” id., at
413, the Court did not accept that nonhearsay label at face
value. Instead, the Court thoroughly examined the use of
the out-of-court confession and the efficacy of a limiting
instruction before concluding that the Confrontation
Clause was satisfied “[i]n this context.” Id., at 417.
   Unlike the confession in Street, statements introduced
to explain the basis of an expert’s opinion are not intro-
duced for a plausible nonhearsay purpose. There is no
meaningful distinction between disclosing an out-of-court
statement so that the factfinder may evaluate the expert’s
opinion and disclosing that statement for its truth. “To
use the inadmissible information in evaluating the ex-
pert’s testimony, the jury must make a preliminary judg-
4                       WILLIAMS v. ILLINOIS

                  THOMAS, J., concurring in judgment

ment about whether this information is true.” D. Kaye, D.
Bernstein, & J. Mnookin, The New Wigmore: A Treatise
on Evidence: Expert Evidence §4.10.1, p. 196 (2d ed. 2011)
(hereinafter Kaye). “If the jury believes that the basis
evidence is true, it will likely also believe that the expert’s
reliance is justified; inversely, if the jury doubts the accu-
racy or validity of the basis evidence, it will be skeptical of
the expert’s conclusions.” Ibid.1
  Contrary to the plurality’s suggestion, this common-
sense conclusion is not undermined by any longstand-
ing historical practice exempting expert basis testimony
from the rigors of the Confrontation Clause. Prior to the
adoption of the Federal Rules of Evidence in 1975, an
expert could render an opinion based only on facts that the
expert had personally perceived or facts that the expert
learned at trial, either by listening to the testimony of
other witnesses or through a hypothetical question based
on facts in evidence. See Advisory Committee’s Notes on
Fed. Rule Evid. 703, 

. App., p. 361; 29 C. Wright
& V. Gold, Federal Practice and Procedure §6271,
pp. 300–301 (1997) (hereinafter Wright); 1 K. Broun et al.,
McCormick on Evidence §14, p. 86 (6th ed. 2006) (herein-
after Broun); Kaye §4.6, at 156–157. In those situations,
there was little danger that the expert would rely on
testimonial hearsay that was not subject to confrontation
because the expert and the witnesses on whom he relied
were present at trial. It was not until 1975 that the uni-
——————
  1 The plurality relies heavily on the fact that this case involved a

bench trial, emphasizing that a judge sitting as factfinder is pre-
sumed—more so than a jury—to “understand the limited reason for the
disclosure” of basis testimony and to “not rely on that information for
any improper purpose.” Ante, at 15. Even accepting that presumption,
the point is not that the factfinder is unable to understand the restricted
purpose for basis testimony. Instead, the point is that the purport-
edly “limited reason” for such testimony—to aid the factfinder in
evaluating the expert’s opinion—necessarily entails an evaluation of
whether the basis testimony is true.
                    Cite as: 567 U. S. ____ (2012)                   5

                 THOMAS, J., concurring in judgment

verse of facts upon which an expert could rely was ex-
panded to include facts of the case that the expert learned
out of court by means other than his own perception. 1
Broun §14, at 87; Kaye §4.6, at 157. It is the expert’s
disclosure of those facts that raises Confrontation Clause
concerns.2
                             B
   Those concerns are fully applicable in this case. Lamba-
tos opined that petitioner’s DNA profile matched the male
profile derived from L. J.’s vaginal swabs. In reaching
that conclusion, Lambatos relied on Cellmark’s out-of-
court statements that the profile it reported was in fact
derived from L. J.’s swabs, rather than from some other
source. Thus, the validity of Lambatos’ opinion ultimately
turned on the truth of Cellmark’s statements. The plural-
ity’s assertion that Cellmark’s statements were merely
relayed to explain “the assumptions on which [Lambatos’]
opinion rest[ed],” ante, at 3, overlooks that the value of
Lambatos’ testimony depended on the truth of those very
assumptions.3
——————
   2 In its discussion of history, the plurality relies on Beckwith v.

Sydebotham, 1 Camp. 116, 170 Eng. Rep. 897 (K. B. 1807). In that
case, experts were asked to render opinions on a ship’s seaworthiness
based on facts read into court from the sworn ex parte deposition of a
witness who purported to have seen the ship’s deficiencies. To be sure,
Beckwith involved expert reliance on testimonial hearsay. But Beck-
with was an English case decided after the ratification of the Confron-
tation Clause, and this form of expert testimony does not appear to
have been a common feature of early American evidentiary practice.
See 29 Wright §6271, at 300–301; 1 Broun §14, at 86–87; Kaye §4.6, at
156–157.
   3 Cellmark’s statements were not introduced for the nonhearsay pur-

pose of showing their effect on Lambatos—i.e., to explain what prompted
her to search the DNA database for a match. See, e.g., 30B M. Graham,
Federal Practice and Procedure §7034.1, pp. 521–529 (interim ed. 2011)
(noting that out-of-court statements introduced for their effect on
listener do not implicate the Confrontation Clause). The statements
6                      WILLIAMS v. ILLINOIS

                  THOMAS, J., concurring in judgment

   It is no answer to say that other nonhearsay evidence
established the basis of the expert’s opinion. Here, Lam-
batos disclosed Cellmark’s statements that it generated a
male DNA profile from L. J.’s swabs, but other evidence
showed that L. J.’s swabs contained semen and that the
swabs were shipped to and received from Cellmark. Ante,
at 5–6. That evidence did not render Cellmark’s state-
ments superfluous. Of course, evidence that Cellmark
received L. J.’s swabs and later produced a DNA profile is
some indication that Cellmark in fact generated the profile
from those swabs, rather than from some other source (or
from no source at all). Cf. Melendez-Diaz v. Massachu-
setts, 

, 319 (2009) (citing brief that describes
“cases of documented ‘drylabbing’ where forensic analysts
report results of tests that were never performed,” includ-
ing DNA tests). But the only direct evidence to that effect
was Cellmark’s statement, which Lambatos relayed to the
factfinder. In any event, the factfinder’s ability to rely on
other evidence to evaluate an expert’s opinion does not
alter the conclusion that basis testimony is admitted for
its truth. The existence of other evidence corroborating
the basis testimony may render any Confrontation Clause
violation harmless, but it does not change the purpose of
such testimony and thereby place it outside of the reach of
the Confrontation Clause.4 I would thus conclude that
——————
that Lambatos conveyed went well beyond what was necessary to
explain why she performed the search. Lambatos did not merely
disclose that she received a DNA profile from Cellmark. Rather, she
further disclosed Cellmark’s statements that the profile was “male” and
that it was “found in semen from the vaginal swabs of [L. J.].” App. 56.
Those facts had nothing to do with her decision to conduct a search.
They were introduced for their truth.
  4 The plurality concludes that the Confrontation Clause would not

be implicated here “even if the record did not contain any [other] evi-
dence that could rationally support a finding that Cellmark produced a
scientifically reliable DNA profile based on L. J.’s vaginal swab.” Ante,
at 22. But, far from establishing a “legitimate” nonhearsay purpose for
                     Cite as: 567 U. S. ____ (2012)                     7

                  THOMAS, J., concurring in judgment

Cellmark’s statements were introduced for their truth.
                              C
   The plurality’s contrary conclusion may seem of little
consequence to those who view DNA testing and other
forms of “hard science” as intrinsically reliable. But see
Melendez-Diaz, supra, at 318 (“Forensic evidence is not
uniquely immune from the risk of manipulation”). Today’s
holding, however, will reach beyond scientific evidence to
ordinary out-of-court statements. For example, it is not
uncommon for experts to rely on interviews with third
parties in forming their opinions. See, e.g., People v. Gold-
stein, 

 119, 123–124, 

, 729–730
(2005) (psychiatrist disclosed statements made by the
defendant’s acquaintances as part of the basis of her opin-
ion that the defendant was motivated to kill by his feelings
of sexual frustration).
   It is no answer to say that “safeguards” in the rules of
evidence will prevent the abuse of basis testimony. Ante,
at 26. To begin with, courts may be willing to conclude
that an expert is not acting as a “mere condui[t]” for hear-
say, ante, at 27, as long as he simply provides some opin-
ion based on that hearsay. See Brief for Respondent 18,
n. 4 (collecting cases). In addition, the hearsay may be the
kind of fact on which experts in a field reasonably rely.
See Fed. Rule Evid. 703; Goldstein, supra, at 125, 

, at 731 (evidence showed that reputable psychia-
trists relied upon third-party interviews in forming their
——————
Cellmark’s statements, Tennessee v. Street, 

, 417 (1985), a
complete lack of other evidence tending to prove the facts conveyed by
Cellmark’s statements would completely refute the not-for-its-truth
rationale. The trial court, in announcing its verdict, expressly concluded
that petitioner’s DNA matched the “DNA . . . in the semen recovered
from the victim’s vagina.” 4 R. JJJ151. Absent other evidence, it would
have been impossible for the trial court to reach that conclusion with-
out relying on the truth of Cellmark’s statement that its test results
were based on the semen from L. J.’s swabs.
8                   WILLIAMS v. ILLINOIS

               THOMAS, J., concurring in judgment

opinions). Of course, some courts may determine that
hearsay of this sort is not substantially more probative
than prejudicial and therefore should not be disclosed un-
der Rule 703. But that balancing test is no substitute
for a constitutional provision that has already struck the
balance in favor of the accused. See Crawford, 541 U. S.,
at 61 (“[The Confrontation Clause] commands, not that
evidence be reliable, but that reliability be assessed in a
particular manner: by testing in the crucible of cross-
examination”).
                                II

                                  

                                A

   Having concluded that the statements at issue here
were introduced for their truth, I turn to whether they
were “testimonial” for purposes of the Confrontation
Clause. In Crawford, the Court explained that “[t]he text
of the Confrontation Clause . . . applies to ‘witnesses’
against the accused—in other words, those who ‘bear
testimony.’ ” Id., at 51 (quoting 2 N. Webster, An Ameri-
can Dictionary of the English Language (1828)). “ ‘Testi-
mony,’ ” in turn, is “ ‘[a] solemn declaration or affirmation
made for the purpose of establishing or proving some
fact.’ ” 541 U. S., at 51. In light of its text, I continue to
think that the Confrontation Clause regulates only the use
of statements bearing “indicia of solemnity.” Davis v.
Washington, 

, 836–837, 840 (2006) (THOMAS,
J., concurring in judgment in part and dissenting in part).
This test comports with history because solemnity marked
the practices that the Confrontation Clause was designed
to eliminate, namely, the ex parte examination of wit-
nesses under the English bail and committal statutes passed
during the reign of Queen Mary. See id., at 835; Bryant,
562 U. S., at ___ (THOMAS, J., concurring in judgment)
(slip op., at 1); Crawford, supra, at 43–45. Accordingly, I
have concluded that the Confrontation Clause reaches
                    Cite as: 567 U. S. ____ (2012)                   9

                 THOMAS, J., concurring in judgment

“ ‘formalized testimonial materials,’ ” such as depositions,
affidavits, and prior testimony, or statements resulting
from “ ‘formalized dialogue,’ ” such as custodial interroga-
tion. Bryant, supra, at ___ (slip op., at 2); see also Davis,
supra, at 836–837.5
    Applying these principles, I conclude that Cellmark’s
report is not a statement by a “witnes[s]” within the mean-
ing of the Confrontation Clause. The Cellmark report
lacks the solemnity of an affidavit or deposition, for it is
neither a sworn nor a certified declaration of fact. No-
where does the report attest that its statements accurately
reflect the DNA testing processes used or the results ob-
tained. See Report of Laboratory Examination, Lodging
of Petitioner. The report is signed by two “reviewers,” but
they neither purport to have performed the DNA testing
nor certify the accuracy of those who did. See ibid. And,
although the report was produced at the request of law
enforcement, it was not the product of any sort of formal-
ized dialogue resembling custodial interrogation.
    The Cellmark report is distinguishable from the labora-
tory reports that we determined were testimonial in
Melendez-Diaz, 

, and in Bullcoming v. New
Mexico, 

___ (2011). In Melendez-Diaz, the re-
ports in question were “sworn to before a notary public
by [the] analysts” who tested a substance for cocaine. 557
U. S., at 308. In Bullcoming, the report, though unsworn,
included a “Certificate of Analyst” signed by the forensic
analyst who tested the defendant’s blood sample. 564
U. S., at ___ (slip op., at 3). The analyst “affirmed that
——————
  5 In addition, I have stated that, because the Confrontation Clause

“sought to regulate prosecutorial abuse occurring through use of
ex parte statements,” it “also reaches the use of technically informal
statements when used to evade the formalized process.” Davis, 547
U. S., at 838 (opinion concurring in judgment in part and dissenting in
part). But, in this case, there is no indication that Cellmark’s state-
ments were offered “in order to evade confrontation.” Id., at 840.
10                  WILLIAMS v. ILLINOIS

               THOMAS, J., concurring in judgment

‘[t]he seal of th[e] sample was received intact and broken
in the laboratory,’ that ‘the statements in [the analyst’s
block of the report] are correct,’ and that he had ‘followed
the procedures set out on the reverse of th[e] report.’ ”
Ibid.
   The dissent insists that the Bullcoming report and
Cellmark’s report are equally formal, separated only by
such “minutia” as the fact that Cellmark’s report “is not
labeled a ‘certificate.’ ” Post, at 22–23 (opinion of KAGAN,
J.). To the contrary, what distinguishes the two is that
Cellmark’s report, in substance, certifies nothing. See su-
pra, at 9. That distinction is constitutionally significant
because the scope of the confrontation right is properly
limited to extrajudicial statements similar in solemnity to
the Marian examination practices that the Confrontation
Clause was designed to prevent. See Davis, supra, at 835–
836 (opinion of THOMAS, J.). By certifying the truth of the
analyst’s representations, the unsworn Bullcoming report
bore “a ‘striking resemblance,’ ” 547 U. S., at 837 (quot-
ing Crawford, 541 U. S., at 52), to the Marian practice in
which magistrates examined witnesses, typically on oath,
and “certif[ied] the results to the court.” Id., at 44. And,
in Melendez-Diaz, we observed that “ ‘certificates’ are
functionally identical to live, in-court testimony, doing
precisely what a witness does on direct examination.” 557
U. S., at 310–311. Cellmark’s report is marked by no such
indicia of solemnity.
   Contrary to the dissent’s suggestion, acknowledging
that the Confrontation Clause is implicated only by for-
malized statements that are characterized by solemnity
will not result in a prosecutorial conspiracy to elude con-
frontation by using only informal extrajudicial statements
against an accused. As I have previously noted, the Con-
frontation Clause reaches bad-faith attempts to evade the
formalized process. See supra, at 9, n. 5 (quoting Davis,
547 U. S., at 838). Moreover, the prosecution’s use of
                  Cite as: 567 U. S. ____ (2012)           11

               THOMAS, J., concurring in judgment

informal statements comes at a price. As the dissent
recognizes, such statements are “less reliable” than for-
malized statements, post, at 24, and therefore less persua-
sive to the factfinder. Cf. post, at 21–22, n. 6 (arguing that
prosecutors are unlikely to “forgo DNA evidence in favor of
less reliable eyewitness testimony” simply because the
defendant is entitled to confront the DNA analyst). But,
even assuming that the dissent accurately predicts an
upswing in the use of “less reliable” informal statements,
that result does not “turn the Confrontation Clause upside
down.” Post, at 24. The Confrontation Clause does not
require that evidence be reliable, Crawford, supra, at 61,
but that the reliability of a specific “class of testimonial
statements”—formalized statements bearing indicia of
solemnity—be assessed through cross-examination. See
Melendez-Diaz, 557 U. S., at 309–310.
                             B
   Rather than apply the foregoing principles, the plurality
invokes its “primary purpose” test. The original formula-
tion of that test asked whether the primary purpose of an
extrajudicial statement was “to establish or prove past
events potentially relevant to later criminal prosecution.”
Davis, supra, at 822. I agree that, for a statement to be
testimonial within the meaning of the Confrontation
Clause, the declarant must primarily intend to establish
some fact with the understanding that his statement may
be used in a criminal prosecution. See Bryant, 562 U. S.,
at ___ (SCALIA, J., dissenting) (slip op., at 2–3). But this
necessary criterion is not sufficient, for it sweeps into the
ambit of the Confrontation Clause statements that lack
formality and solemnity and is thus “disconnected from
history.” Davis, supra, at 838–842 (opinion concurring in
judgment in part and dissenting in part); Bryant, supra, at
___ (opinion concurring in judgment) (slip op., at 1). In
addition, a primary purpose inquiry divorced from solem-
12                  WILLIAMS v. ILLINOIS

               THOMAS, J., concurring in judgment

nity is unworkable in practice. Davis, supra, at 839; Bry-
ant, supra, at ___ (slip op., at 1). Statements to police are
often made both to resolve an ongoing emergency and to
establish facts about a crime for potential prosecution.
The primary purpose test gives courts no principled way to
assign primacy to one of those purposes. Davis, supra, at
839. The solemnity requirement is not only true to the
text and history of the Confrontation Clause, but goes a
long way toward resolving that practical difficulty. If a
statement bears the formality and solemnity necessary to
come within the scope of the Clause, it is highly unlikely
that the statement was primarily made to end an ongoing
emergency.
  The shortcomings of the original primary purpose test
pale in comparison, however, to those plaguing the refor-
mulated version that the plurality suggests today. The
new primary purpose test asks whether an out-of-court
statement has “the primary purpose of accusing a targeted
individual of engaging in criminal conduct.” Ante, at 29.
That test lacks any grounding in constitutional text, in
history, or in logic.
  The new test first requires that an out-of-court state-
ment be made “for the purpose of proving the guilt of
a particular criminal defendant.” Ante, at 30 (emphasis
added). Under this formulation, statements made “before
any suspect was identified” are beyond the scope of the
Confrontation Clause. See ante, at 3. There is no textual
justification, however, for limiting the confrontation right
to statements made after the accused’s identity became
known. To be sure, the Sixth Amendment right to con-
frontation attaches “[i]n . . . criminal prosecutions,” at
which time the accused has been identified and appre-
hended. But the text of the Confrontation Clause does not
constrain the time at which one becomes a “witnes[s].”
Indeed, we have previously held that a declarant may
become a “witnes[s]” before the accused’s prosecution. See
                  Cite as: 567 U. S. ____ (2012)             13

                THOMAS, J., concurring in judgment

Crawford, 541 U. S., at 50–51 (rejecting the view that the
Confrontation Clause applies only to in-court testimony).
  Historical practice confirms that a declarant could
become a “witnes[s]” before the accused’s identity was
known. As previously noted, the confrontation right was
a response to ex parte examinations of witnesses in 16th-
century England. Such examinations often occurred after
an accused was arrested or bound over for trial, but some
examinations occurred while the accused remained “un-
known or fugitive.” J. Langbein, Prosecuting Crime in the
Renaissance 90 (1974) (describing examples, including the
deposition of a victim who was swindled out of 20 shillings
by a “ ‘cunning man’ ”); see also 1 J. Stephen, A History of
the Criminal Law of England 217–218 (1883) (describ-
ing the sworn examinations of witnesses by coroners, who
were charged with investigating suspicious deaths by
asking local citizens if they knew “who [was] culpable
either of the act or of the force” (internal quotation marks
omitted)).
  There is also little logical justification for the plurality’s
rule. The plurality characterizes Cellmark’s report as a
statement elicited by police and made by Cellmark not “to
accuse petitioner or to create evidence for use at trial,” but
rather to resolve the ongoing emergency posed by “a dan-
gerous rapist who was still at large.” Ante, at 31. But, as
I have explained, that distinction is unworkable in light of
the mixed purposes that often underlie statements to the
police. See supra, at 12. The difficulty is only compound-
ed by the plurality’s attempt to merge the purposes of both
the police and the declarant. See ante, at 29; Bryant,
supra, at ___–___ (majority opinion) (slip op., at 20–23).
  But if one purpose must prevail, here it should surely be
the evidentiary one, whether viewed from the perspective
of the police, Cellmark, or both. The police confirmed the
presence of semen on L. J.’s vaginal swabs on February 15,
2000, placed the swabs in a freezer, and waited until
14                  WILLIAMS v. ILLINOIS

               THOMAS, J., concurring in judgment

November 28, 2000, to ship them to Cellmark. App. 30–
34, 51–52. Cellmark, in turn, did not send its report to
the police until April 3, 2001, id., at 54, over a year
after L. J.’s rape. Given this timeline, it strains credulity
to assert that the police and Cellmark were primarily
concerned with the exigencies of an ongoing emergency,
rather than with producing evidence in the ordinary course.
   In addition to requiring that an out-of-court statement
“targe[t]” a particular accused, the plurality’s new primary
purpose test also considers whether the statement is so
“inherently inculpatory,” ante, at 3, that the declarant
should have known that his statement would incriminate
the accused. In this case, the plurality asserts that “[t]he
technicians who prepare a DNA profile generally have no
way of knowing whether it will turn out to be incriminat-
ing or exonerating—or both,” ante, at 32, and thus “no one
at Cellmark could have possibly known that the profile
that it produced would turn out to inculpate petitioner,”
ante, at 31.
   Again, there is no textual justification for this limitation
on the scope of the Confrontation Clause. In Melendez-
Diaz, we held that “[t]he text of the [Sixth] Amendment
contemplates two classes of witnesses—those against the
defendant and those in his favor.” 557 U. S., at 313–314.
We emphasized that “there is not a third category of wit-
nesses, helpful to the prosecution, but somehow immune
from confrontation.” Id., at 314. Thus, the distinction
between those who make “inherently inculpatory” state-
ments and those who make other statements that are
merely “helpful to the prosecution” has no foundation in
the text of the Amendment.
   It is also contrary to history. The 16th-century Marian
statutes instructed magistrates to transcribe any infor-
mation by witnesses that “ ‘shall be material to prove the
felony.’ ” See, e.g., 1 Stephen, supra, at 219 (quoting 1 & 2
Phil. & Mary, ch. 13 (1554)). Magistrates in the 17th and
                     Cite as: 567 U. S. ____ (2012)                  15

                  THOMAS, J., concurring in judgment

18th centuries were also advised by practice manuals to
take the ex parte examination of a witness even if his evi-
dence was “weak” or the witness was “unable to inform
any material thing against” an accused. J. Beattie, Crime
and the Courts in England: 1660–1800, p. 272 (1986)
(internal quotation marks omitted). Thus, neither law nor
practice limited ex parte examinations to those witnesses
who made “inherently inculpatory” statements.
   This requirement also makes little sense. A statement
that is not facially inculpatory may turn out to be highly
probative of a defendant’s guilt when considered with
other evidence. Recognizing this point, we previously
rejected the view that a witness is not subject to confron-
tation if his testimony is “inculpatory only when taken
together with other evidence.” Melendez-Diaz, supra, at
313. I see no justification for reviving that discredited
approach, and the plurality offers none.6
                          *      *     *
   Respondent and its amici have emphasized the econom-
ic and logistical burdens that would be visited upon States
should every analyst who reports DNA results be required
to testify at trial. See, e.g., ante, at 32 (citing brief stating
that some crime labs use up to 12 technicians when test-
ing a DNA sample). These burdens are largely the prod-
uct of a primary purpose test that reaches out-of-court
statements well beyond the historical scope of the Con-
frontation Clause and thus sweeps in a broad range of
sources on which modern experts regularly rely. The
——————
  6 The plurality states that its test “will not prejudice any defendant

who really wishes to probe the reliability” of out-of-court statements
introduced in his case because the person or persons who made the
statements “may always be subpoenaed by the defense and questioned
at trial.” Ante, at 4. Melendez-Diaz rejected this reasoning as well,
holding that the defendant’s subpoena power “is no substitute for the
right of confrontation.” 557 U. S., at 324.
16                  WILLIAMS v. ILLINOIS

               THOMAS, J., concurring in judgment

proper solution to this problem is not to carve out a Con-
frontation Clause exception for expert testimony that is
rooted only in legal fiction. See ante, at 3. Nor is it to
create a new primary purpose test that ensures that DNA
evidence is treated differently. See ibid. Rather, the
solution is to adopt a reading of the Confrontation Clause
that respects its historically limited application to a nar-
row class of statements bearing indicia of solemnity. In
forgoing that approach, today’s decision diminishes the
Confrontation Clause’s protection in cases where experts
convey the contents of solemn, formalized statements to
explain the bases for their opinions. These are the very
cases in which the accused should “enjoy the right . . . to
be confronted with the witnesses against him.”
                 Cite as: 567 U. S. ____ (2012)            1

                     KAGAN, J., dissenting

SUPREME COURT OF THE UNITED STATES
                         _________________

                         No. 10–8505
                         _________________


     SANDY WILLIAMS, PETITIONER v. ILLINOIS
    ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

                                                 

                       ILLINOIS

                               

                        [June 18, 2012] 


   JUSTICE KAGAN, with whom JUSTICE SCALIA, JUSTICE
GINSBURG, and JUSTICE SOTOMAYOR join, dissenting.
   Some years ago, the State of California prosecuted a
man named John Kocak for rape. At a preliminary hear-
ing, the State presented testimony from an analyst at the
Cellmark Diagnostics Laboratory—the same facility used
to generate DNA evidence in this case. The analyst had
extracted DNA from a bloody sweatshirt found at the
crime scene and then compared it to two control samples—
one from Kocak and one from the victim. The analyst’s
report identified a single match: As she explained on
direct examination, the DNA found on the sweatshirt
belonged to Kocak.          But after undergoing cross-
examination, the analyst realized she had made a mortify-
ing error. She took the stand again, but this time to admit
that the report listed the victim’s control sample as coming
from Kocak, and Kocak’s as coming from the victim. So
the DNA on the sweatshirt matched not Kocak, but the
victim herself. See Tr. in No. SCD110465 (Super. Ct. San
Diego Cty., Cal., Nov. 17, 1995), pp. 3–4 (“I’m a little hys-
terical right now, but I think . . . the two names should be
switched”), online at http: //www.nlada.org/forensics/for_
lib/Documents/1037341561.0/JohnIvanKocak.pdf (as vis-
ited June 15, 2012, and available in Clerk of Court’s case
file). In trying Kocak, the State would have to look else-
where for its evidence.
2                  WILLIAMS v. ILLINOIS

                    KAGAN, J., dissenting

   Our Constitution contains a mechanism for catching
such errors—the Sixth Amendment’s Confrontation
Clause. That Clause, and the Court’s recent cases inter-
preting it, require that testimony against a criminal de-
fendant be subject to cross-examination. And that com-
mand applies with full force to forensic evidence of the
kind involved in both the Kocak case and this one. In two
decisions issued in the last three years, this Court held
that if a prosecutor wants to introduce the results of fo-
rensic testing into evidence, he must afford the defendant
an opportunity to cross-examine an analyst responsible for
the test. Forensic evidence is reliable only when properly
produced, and the Confrontation Clause prescribes a par-
ticular method for determining whether that has hap-
pened. The Kocak incident illustrates how the Clause is
designed to work: Once confronted, the analyst discovered
and disclosed the error she had made. That error would
probably not have come to light if the prosecutor had
merely admitted the report into evidence or asked a third
party to present its findings. Hence the genius of an 18th-
century device as applied to 21st-century evidence: Cross-
examination of the analyst is especially likely to reveal
whether vials have been switched, samples contaminated,
tests incompetently run, or results inaccurately recorded.
   Under our Confrontation Clause precedents, this is
an open-and-shut case. The State of Illinois prosecuted
Sandy Williams for rape based in part on a DNA profile
created in Cellmark’s laboratory. Yet the State did not
give Williams a chance to question the analyst who pro-
duced that evidence. Instead, the prosecution introduced
the results of Cellmark’s testing through an expert wit-
ness who had no idea how they were generated. That
approach—no less (perhaps more) than the confrontation-
free methods of presenting forensic evidence we have
formerly banned—deprived Williams of his Sixth Amend-
ment right to “confron[t] . . . the witnesses against him.”
                  Cite as: 567 U. S. ____ (2012)            3

                      KAGAN, J., dissenting

   The Court today disagrees, though it cannot settle on a
reason why. JUSTICE ALITO, joined by three other Jus-
tices, advances two theories—that the expert’s summary of
the Cellmark report was not offered for its truth, and
that the report is not the kind of statement triggering the
Confrontation Clause’s protection. In the pages that
follow, I call JUSTICE ALITO’s opinion “the plurality,”
because that is the conventional term for it. But in all
except its disposition, his opinion is a dissent: Five Jus-
tices specifically reject every aspect of its reasoning
and every paragraph of its explication. See ante, at 1
(THOMAS, J., concurring in judgment) (“I share the dis-
sent’s view of the plurality’s flawed analysis”). JUSTICE
THOMAS, for his part, contends that the Cellmark report
is nontestimonial on a different rationale. But no other
Justice joins his opinion or subscribes to the test he offers.
   That creates five votes to approve the admission of the
Cellmark report, but not a single good explanation. The
plurality’s first rationale endorses a prosecutorial dodge;
its second relies on distinguishing indistinguishable foren-
sic reports. JUSTICE THOMAS’s concurrence, though posit-
ing an altogether different approach, suffers in the end
from similar flaws. I would choose another path—to
adhere to the simple rule established in our decisions, for
the good reasons we have previously given. Because de-
fendants like Williams have a constitutional right to con-
front the witnesses against them, I respectfully dissent
from the Court’s fractured decision.
                            I
  Our modern Confrontation Clause doctrine began with
Crawford v. Washington, 

 (2004). About a
quarter century earlier, we had interpreted the Clause to
allow the admission of any out-of-court statement falling
within a “firmly rooted hearsay exception” or carrying
“particularized guarantees of trustworthiness.” Ohio v.
4                    WILLIAMS v. ILLINOIS

                      KAGAN, J., dissenting

Roberts, 

, 66 (1980). But in Crawford, we
concluded that our old approach was misguided. Drawing
on historical research about the Clause’s purposes, we
held that the prosecution may not admit “testimonial
statements of a witness who [does] not appear at trial
unless he [is] unavailable to testify, and the defendant . . .
had a prior opportunity for cross-examination.” 541 U. S.,
at 53–54. That holding has two aspects. First, the Con-
frontation Clause applies only to out-of-court statements
that are “testimonial.” Second, where the Clause applies,
it guarantees to a defendant just what its name sug-
gests—the opportunity to cross-examine the person who
made the statement. See id., at 59.
    A few years later, we made clear that Crawford’s rule
reaches forensic reports. In Melendez-Diaz v. Massachu­

setts, 

 (2009), the Commonwealth introduced
a laboratory’s “ ‘certificates of analysis’ ” stating that a sub-
stance seized from the defendant was cocaine. Id., at
308. We held that the certificates fell within the Clause’s
“ ‘core class of testimonial statements’ ” because they had
a clear “evidentiary purpose”: They were “ ‘made under
circumstances which would lead an objective witness
reasonably to believe that [they] would be available for use
at a later trial.’ ” Id., at 310–311 (quoting Crawford, 541
U. S., at 51–52). Accordingly, we ruled, the defendant had
a right to cross-examine the analysts who had authored
them.      In reaching that conclusion, we rejected the
Commonwealth’s argument that the Confrontation Clause
should not apply because the statements resulted from
“ ‘neutral scientific testing,’ ” and so were presumptively
reliable. 557 U. S., at 318. The Clause, we noted,
commands that “ ‘reliability be assessed in a particular
manner’ ”—through “ ‘testing in the crucible of cross-
examination.’ ” Id., at 317 (quoting Crawford, 541 U. S., at
61). Further, we doubted that the testing summarized
in the certificates was “as neutral or as reliable” as the
                  Cite as: 567 U. S. ____ (2012)            5

                      KAGAN, J., dissenting

Commonwealth suggested. Citing chapter and verse from
various studies, we concluded that “[f]orensic evidence is
not uniquely immune from the risk of manipulation” and
mistake. 557 U. S., at 318; see id., at 319.
   And just two years later (and just one year ago), we
reiterated Melendez-Diaz’s analysis when faced with a
State’s attempt to evade it. In Bullcoming v. New Mexico,

___ (2011), a forensic report showed the defend-
ant’s blood-alcohol concentration to exceed the legal limit
for drivers. The State tried to introduce that finding
through the testimony of a person who worked at the
laboratory but had not performed or observed the blood
test or certified its results. We held that Melendez-Diaz
foreclosed that tactic. The report, we stated, resembled
the certificates in Melendez-Diaz in “all material respects,”
564 U. S., at ___ (slip op., at 15): Both were signed docu-
ments providing the results of forensic testing designed to
“ ‘prov[e] some fact’ in a criminal proceeding,” id., at ___
(slip op., at 14) (quoting Melendez-Diaz, 557 U. S., at 310).
And the State’s resort to a “surrogate” witness, in place
of the analyst who produced the report, did not satisfy the
Confrontation Clause. Bullcoming, 564 U. S., at ___ (slip
op., at 12). Only the presence of “that particular scientist,”
we reasoned, would enable Bullcoming’s counsel to ask
“questions designed to reveal whether incompetence . . . or
dishonesty” had tainted the results. Id., at ___, ___ (slip
op., at 2, 12). Repeating the refrain of Melendez-Diaz, we
held that “[t]he accused’s right is to be confronted with”
the actual analyst, unless he is unavailable and the ac-
cused “had an opportunity, pretrial, to cross-examine”
him. Bullcoming, 564 U. S., at ___ (slip op., at 2).
   This case is of a piece. The report at issue here shows a
DNA profile produced by an analyst at Cellmark’s labora-
tory, allegedly from a vaginal swab taken from a young
woman, L. J., after she was raped. That report is identical
to the one in Bullcoming (and Melendez-Diaz) in “all mate-
6                  WILLIAMS v. ILLINOIS

                     KAGAN, J., dissenting

rial respects.” 564 U. S., at ___ (slip op., at 15). Once
again, the report was made to establish “ ‘some fact’ in a
criminal proceeding”—here, the identity of L. J.’s attacker.
Id., at ___ (slip op., at 14) (quoting Melendez-Diaz, 557
U. S., at 310); see infra, at 20. And once again, it details
the results of forensic testing on evidence gathered by the
police. Viewed side-by-side with the Bullcoming report,
the Cellmark analysis has a comparable title; similarly
describes the relevant samples, test methodology, and
results; and likewise includes the signatures of laboratory
officials. Compare Cellmark Diagnostics Report of Labor-
atory Examination (Feb. 15, 2001), Lodging of Petitioner
with App. in Bullcoming v. New Mexico, O. T. 2010, No.
09–10876, pp. 62–65. So under this Court’s prior analysis,
the substance of the report could come into evidence only
if Williams had a chance to cross-examine the responsible
analyst.
   But that is not what happened. Instead, the prosecutor
used Sandra Lambatos—a state-employed scientist who
had not participated in the testing—as the conduit for this
piece of evidence. Lambatos came to the stand after two
other state analysts testified about forensic tests they had
performed. One recounted how she had developed a DNA
profile of Sandy Williams from a blood sample drawn after
his arrest. And another told how he had confirmed the
presence of (unidentified) semen on the vaginal swabs
taken from L. J. All this was by the book: Williams had
an opportunity to cross-examine both witnesses about the
tests they had run. But of course, the State still needed to
supply the missing link—it had to show that DNA found
in the semen on L. J.’s vaginal swabs matched Williams’s
DNA. To fill that gap, the prosecutor could have called the
analyst from Cellmark to testify about the DNA profile she
had produced from the swabs. But instead, the State
called Lambatos as an expert witness and had her testify
that the semen on those swabs contained Sandy Wil-
                    Cite as: 567 U. S. ____ (2012)         7

                        KAGAN, J., dissenting

liams’s DNA:
    “Q Was there a computer match generated of the
    male DNA profile found in semen from the vaginal
    swabs of [L. J.] to a male DNA profile that had been
    identified as having originated from Sandy Williams?

    “A Yes, there was.

    “Q Did you compare the semen . . . from the vaginal
    swabs of [L. J.] to the male DNA profile . . . from the
    blood of Sandy Williams?

    “A Yes, I did.

    .           .               .               .    .

    “Q [I]s the semen identified in the vaginal swabs of
    [L. J.] consistent with having originated from Sandy
    Williams?

    “A Yes.” App. 56–57.
And so it was Lambatos, rather than any Cellmark em-
ployee, who informed the trier of fact that the testing of
L. J.’s vaginal swabs had produced a male DNA profile
implicating Williams.
  Have we not already decided this case? Lambatos’s
testimony is functionally identical to the “surrogate testi-
mony” that New Mexico proffered in Bullcoming, which
did nothing to cure the problem identified in Melendez-
Diaz (which, for its part, straightforwardly applied our
decision in Crawford). Like the surrogate witness in
Bullcoming, Lambatos “could not convey what [the actual
analyst] knew or observed about the events . . . , i.e., the
particular test and testing process he employed.” Bull­
coming, 564 U. S., at ___ (slip op., at 12). “Nor could such
8                  WILLIAMS v. ILLINOIS

                     KAGAN, J., dissenting

surrogate testimony expose any lapses or lies” on the
testing analyst’s part. Ibid. Like the lawyers in Melendez-
Diaz and Bullcoming, Williams’s attorney could not ask
questions about that analyst’s “proficiency, the care he
took in performing his work, and his veracity.” 564 U. S.,
at ___, n. 7 (slip op., at 12, n. 7). He could not probe
whether the analyst had tested the wrong vial, inverted
the labels on the samples, committed some more technical
error, or simply made up the results. See App. to Brief for
Public Defender Service for the District of Columbia et al.
as Amici Curiae 5a, 11a (describing mistakes and fraud
at Cellmark’s laboratory). Indeed, Williams’s lawyer was
even more hamstrung than Bullcoming’s. At least the
surrogate witness in Bullcoming worked at the relevant
laboratory and was familiar with its procedures. That is
not true of Lambatos: She had no knowledge at all of
Cellmark’s operations. Indeed, for all the record discloses,
she may never have set foot in Cellmark’s laboratory.
   Under our case law, that is sufficient to resolve this
case. “[W]hen the State elected to introduce” the sub-
stance of Cellmark’s report into evidence, the analyst who
generated that report “became a witness” whom Williams
“had the right to confront.” Bullcoming, 564 U. S., at ___
(slip op., at 13). As we stated just last year, “Our prece-
dent[s] cannot sensibly be read any other way.” Ibid.
                              II
  The plurality’s primary argument to the contrary tries
to exploit a limit to the Confrontation Clause recognized in
Crawford. “The Clause,” we cautioned there, “does not bar
the use of testimonial statements for purposes other than
establishing the truth of the matter asserted.” 541 U. S.,
at 59–60, n. 9 (citing Tennessee v. Street, 

,
414 (1985)). The Illinois Supreme Court relied on that
statement in concluding that Lambatos’s testimony was
permissible. On that court’s view, “Lambatos disclosed
                 Cite as: 567 U. S. ____ (2012)           9

                     KAGAN, J., dissenting

the underlying facts from Cellmark’s report” not for their
truth, but “for the limited purpose of explaining the basis
for her [expert] opinion,” so that the factfinder could as-
sess that opinion’s value. 

, 150, 

 268, 282 (2010). The plurality wraps itself in that
holding, similarly asserting that Lambatos’s recitation of
Cellmark’s findings, when viewed through the prism of
state evidence law, was not introduced to establish “the
truth of any . . . matter concerning [the] Cellmark” report.
Ante, at 16; see ante, at 2, 24–25. But five Justices agree,
in two opinions reciting the same reasons, that this
argument has no merit: Lambatos’s statements about
Cellmark’s report went to its truth, and the State could
not rely on her status as an expert to circumvent the
Confrontation Clause’s requirements. See ante, at 2–8
(opinion of THOMAS, J.).
  To see why, start with the kind of case Crawford had in
mind. In acknowledging the not-for-the-truth carveout
from the Clause, the Court cited Tennessee v. Street as
exemplary. See Crawford, 541 U. S., at 59–60, n. 9.
There, Street claimed that his stationhouse confession of
murder was a sham: A police officer, he charged, had read
aloud his alleged accomplice’s confession and forced him to
repeat it. To help rebut that defense, the State introduced
the other confession into the record, so the jury could see
how it differed from Street’s. This Court rejected Street’s
Confrontation Clause claim because the State had offered
the out-of-court statement not to prove “the truth of
[the accomplice’s] assertions” about the murder, but only to
disprove Street’s claim of how the police elicited his con-
fession. Street, 471 U. S., at 413. Otherwise said, the
truth of the admitted statement was utterly immaterial;
the only thing that mattered was that the statement
(whether true or false) varied from Street’s.
  The situation could not be more different when a wit-
ness, expert or otherwise, repeats an out-of-court state-
10                      WILLIAMS v. ILLINOIS

                          KAGAN, J., dissenting

ment as the basis for a conclusion, because the statement’s
utility is then dependent on its truth. If the statement is
true, then the conclusion based on it is probably true; if
not, not. So to determine the validity of the witness’s
conclusion, the factfinder must assess the truth of the out-
of-court statement on which it relies. That is why the
principal modern treatise on evidence variously calls the
idea that such “basis evidence” comes in not for its truth,
but only to help the factfinder evaluate an expert’s opin-
ion “very weak,” “factually implausible,” “nonsense,” and
“sheer fiction.” D. Kaye, D. Bernstein, & J. Mnookin, The
New Wigmore: Expert Evidence §4.10.1, pp. 196–197 (2d
ed. 2011); id., §4.11.6, at 24 (Supp. 2012). “One can sym-
pathize,” notes that treatise, “with a court’s desire to
permit the disclosure of basis evidence that is quite prob-
ably reliable, such as a routine analysis of a drug, but to
pretend that it is not being introduced for the truth of its
contents strains credibility.” Id., §4.10.1, at 198 (2d ed.
2011); see also, e.g., People v. Goldstein, 

 119,
128, 

, 732–733 (2005) (“The distinction
between a statement offered for its truth and a statement
offered to shed light on an expert’s opinion is not meaning-
ful”). Unlike in Street, admission of the out-of-court
statement in this context has no purpose separate from its
truth; the factfinder can do nothing with it except assess
its truth and so the credibility of the conclusion it serves to
buttress.1

——————
  1 In responding to this reasoning, the plurality confirms it. According

to the plurality, basis evidence supports the “credibility of the expert’s
opinion” by showing that he has relied on, and drawn logical inferences
from, sound “factual premises.” Ante, at 24. Quite right. And that
process involves assessing such premises’ truth: If they are, as the
plurality puts it, “unsupported by other evidence in the record” or
otherwise baseless, they will not “allay [a factfinder’s] fears” about an
“expert’s reasoning.” Ante, at 24–25. I could not have said it any
better.
                  Cite as: 567 U. S. ____ (2012)           11

                      KAGAN, J., dissenting

   Consider a prosaic example not involving scientific ex-
perts. An eyewitness tells a police officer investigating
an assault that the perpetrator had an unusual, star-
shaped birthmark over his left eye. The officer arrests a
person bearing that birthmark (let’s call him Starr) for
committing the offense. And at trial, the officer takes the
stand and recounts just what the eyewitness told him.
Presumably the plurality would agree that such testimony
violates the Confrontation Clause unless the eyewitness is
unavailable and the defendant had a prior opportunity to
cross-examine him. Now ask whether anything changes if
the officer couches his testimony in the following way: “I
concluded that Starr was the assailant because a reliable
eyewitness told me that the assailant had a star-shaped
birthmark and, look, Starr has one just like that.” Surely
that framing would make no constitutional difference,
even though the eyewitness’s statement now explains the
basis for the officer’s conclusion. It remains the case that
the prosecution is attempting to introduce a testimonial
statement that has no relevance to the proceedings apart
from its truth—and that the defendant cannot cross-
examine the person who made it. Allowing the admission
of this evidence would end-run the Confrontation Clause,
and make a parody of its strictures.
   And that example, when dressed in scientific clothing, is
no different from this case. The Cellmark report identified
the rapist as having a particular DNA profile (think of
it as the quintessential birthmark). The Confrontation
Clause prevented the State from introducing that report
into evidence except by calling to the stand the person who
prepared it. See Melendez-Diaz, 557 U. S., at 310–311;
Bullcoming, 564 U. S., at ___ (slip op., at 2). So the State
tried another route—introducing the substance of the re-
port as part and parcel of an expert witness’s conclusion.
In effect, Lambatos testified (like the police officer above):
“I concluded that Williams was the rapist because Cell-
12                     WILLIAMS v. ILLINOIS

                         KAGAN, J., dissenting

mark, an accredited and trustworthy laboratory, says
that the rapist has a particular DNA profile and, look,
Williams has an identical one.” And here too, that form
of testimony should change nothing. The use of the
Cellmark statement remained bound up with its truth,
and the statement came into evidence without any oppor-
tunity for Williams to cross-examine the person who made
it. So if the plurality were right, the State would have a
ready method to bypass the Constitution (as much as in
my hypothetical case); a wink and a nod, and the Confron-
tation Clause would not pose a bar to forensic evidence.
   The plurality tries to make plausible its not-for-the-
truth rationale by rewriting Lambatos’s testimony about
the Cellmark report. According to the plurality, Lambatos
merely “assumed” that Cellmark’s DNA profile came from
L. J.’s vaginal swabs, accepting for the sake of argument
the prosecutor’s premise. Ante, at 18. But that is incor-
rect. Nothing in Lambatos’s testimony indicates that she
was making an assumption or considering a hypothesis.
To the contrary, Lambatos affirmed, without qualification,
that the Cellmark report showed a “male DNA profile
found in semen from the vaginal swabs of [L. J.].” App.
56. Had she done otherwise, this case would be different.
There was nothing wrong with Lambatos’s testifying that
two DNA profiles—the one shown in the Cellmark report
and the one derived from Williams’s blood—matched each
other; that was a straightforward application of Lamba-
tos’s expertise. Similarly, Lambatos could have added
that if the Cellmark report resulted from scientifically
sound testing of L. J.’s vaginal swab, then it would link
Williams to the assault. What Lambatos could not do was
what she did: indicate that the Cellmark report was pro-
duced in this way by saying that L. J.’s vaginal swab
contained DNA matching Williams’s.2 By testifying in
——————
 2 The   plurality suggests that Lambatos’s testimony is merely a mod-
                     Cite as: 567 U. S. ____ (2012)                    13

                          KAGAN, J., dissenting

that manner, Lambatos became just like the surrogate
witness in Bullcoming—a person knowing nothing about
“the particular test and testing process,” but vouching for
them regardless. 564 U. S., at ___ (slip op., at 12). We
have held that the Confrontation Clause requires some-
thing more.
   The plurality also argues that Lambatos’s characteriza-
tion of the Cellmark report did not violate the Confronta-
tion Clause because the case “involve[d] a bench trial.”
Ante, at 19 (emphasis deleted). I welcome the plurality’s
concession that the Clause might forbid presenting Lam-
batos’s statement to a jury, see ante, at 18–19; it indicates
that the plurality realizes that her testimony went beyond
an “assumption.” But the presence of a judge does not
transform the constitutional question. In applying the
Confrontation Clause, we have never before considered
relevant the decisionmaker’s identity. See, e.g., Davis v.
——————
ern, streamlined way of answering hypothetical questions and therefore
raises no constitutional issue, see ante, at 2, 13–15; similarly, the
plurality contends that the difference between what Lambatos said and
what I would allow involves only “slightly revis[ing]” her testimony and
so can be of no consequence, see ante, at 18, n. 3. But the statement “if
X is true, then Y follows” differs materially—and constitutionally—
from the statement “Y is true because X is true (according to Z).” The
former statement is merely a logical proposition, whose validity the
defendant can contest by questioning the speaker. And then, assum-
ing the prosecutor tries to prove the statement’s premise through some
other witness, the defendant can rebut that effort through cross-
examination. By contrast, the latter statement as well contains a
factual allegation (that X is true), which the defendant can only effec-
tively challenge by confronting the person who made it (Z). That is why
recognizing the difference between these two forms of testimony is not
to insist on an archaism or a formality, but to ensure, in line with the
Constitution, that defendants have the ability to confront their accus-
ers. And if prosecutors can easily conform their conduct to that consti-
tutional directive, as the plurality suggests, so much the better: I would
not have thought it a ground of complaint that the Confrontation
Clause, properly understood, manages to protect defendants without
overly burdening the State.
14                  WILLIAMS v. ILLINOIS

                      KAGAN, J., dissenting

Washington, 

 (2006). And this case would
be a poor place to begin. Lambatos’s description of the
Cellmark report was offered for its truth because that is
all such “basis evidence” can be offered for; as described
earlier, the only way the factfinder could consider whether
that statement supported her opinion (that the DNA on
L. J.’s swabs came from Williams) was by assessing the
statement’s truth. See supra, at 9–12. That is so, as a
simple matter of logic, whether the factfinder is a judge or
a jury. And thus, in either case, admission of the state-
ment, without the opportunity to cross-examine, violates
the Confrontation Clause. See ante, at 3–4, n. 1 (opinion
of THOMAS, J.).
   In saying that much, I do not doubt that a judge typi-
cally will do better than a jury in excluding such inadmis-
sible evidence from his decisionmaking process. Perhaps
the judge did so here; perhaps, as the plurality thinks, he un-
derstood that he could not consider Lambatos’s repre-
sentation about the Cellmark report, and found that other,
“circumstantial evidence” established “the source of the
sample that Cellmark tested” and “the reliability of the
Cellmark profile.” See ante, at 22–23. Some indications
are to the contrary: In delivering his verdict, the judge
never referred to the circumstantial evidence the plurality
marshals, but instead focused only on Lambatos’s testi-
mony. See 4 Record JJJ151 (calling Lambatos “the best
DNA witness I have ever heard” and referring to Williams
as “the guy whose DNA, according to the evidence from
the experts, is in the semen recovered from the victim’s
vagina”). But I take the plurality’s point that when read
“[i]n context” the judge’s statements might be “best under-
stood” as meaning something other than what they appear
to say. See ante, at 20, n. 6. Still, that point suggests only
that the admission of Lambatos’s statement was harm-
less—that the judge managed to put it out of mind. After
all, whether a factfinder is confused by an error is a sepa-
                      Cite as: 567 U. S. ____ (2012)                     15

                          KAGAN, J., dissenting

rate question from whether an error has occurred. So the
plurality’s argument does not answer the only question
this case presents: whether a constitutional violation
happened when Lambatos recited the Cellmark report’s
findings.3
   At bottom, the plurality’s not-for-the-truth rationale is a
simple abdication to state-law labels. Although the utility
of the Cellmark statement that Lambatos repeated logi-
cally depended on its truth, the plurality thinks this case
decided by an Illinois rule holding that the facts underly-
ing an expert’s opinion are not admitted for that purpose.
See ante, at 14–18; People v. Pasch, 

, 175–
177, 

, 311 (1992). But we do not typically
allow state law to define federal constitutional require-
ments. And needless to say (or perhaps not), the Confron-
——————
   3 The plurality asserts (without citation) that I am “reach[ing] the

truly remarkable conclusion that the wording of Lambatos’ testimony
confused the trial judge,” ante, at 19, and then spends three pages
explaining why that conclusion is wrong, see ante, at 19–21. But the
plurality is responding to an argument of its own imagining, because I
reach no such conclusion. As I just stated, the trial judge might well
have ignored Lambatos’s statement about the Cellmark report and
relied on other evidence to conclude that “the Cellmark profile was
derived from the sample taken from the victim,” ante, at 19. All I am
saying is that the admission of that statement violated the Confronta-
tion Clause even if the judge ultimately put it aside, because it came
into evidence for nothing other than its truth. See supra, at 9–12.
   Similarly, the plurality claims (still without citation) that I think the
other evidence about the Cellmark report insufficient, see ante, at 21.
But once again, the plurality must be reading someone else’s opinion. I
express no view on sufficiency of the evidence because it is irrelevant to
the Confrontation Clause issue we took this case to decide. It is the
plurality that wrongly links the two, spending another five pages
trumpeting the strength of the Cellmark report, see ante, at 22–24, 32–
33. But the plurality cannot properly decide whether a Confrontation
Clause violation occurred at Williams’s trial by determining that
Williams was guilty. The American criminal justice system works the
opposite way: determining guilt by holding trials in accord with consti-
tutional requirements.
16                  WILLIAMS v. ILLINOIS

                     KAGAN, J., dissenting

tation Clause is a constitutional rule like any other. As
JUSTICE THOMAS observes, even before Crawford, we did
not allow the Clause’s scope to be “dictated by state or
federal evidentiary rules.” See ante, at 2. Indeed, in
Street, we independently reviewed whether an out-of-court
statement was introduced for its truth—the very question
at issue in this case. See 471 U. S., at 413–416. And in
Crawford, we still more firmly disconnected the Confron-
tation Clause inquiry from state evidence law, by overrul-
ing an approach that looked in part to whether an out-
of-court statement fell within a “ ‘firmly rooted hearsay
exception.’ ” 541 U. S., at 60 (quoting Roberts, 448 U. S., at
66). That decision made clear that the Confrontation
Clause’s protections are not coterminous with rules of
evidence. So the plurality’s state-law-first approach would
be an about-face.
  Still worse, that approach would allow prosecutors to do
through subterfuge and indirection what we previously
have held the Confrontation Clause prohibits. Imagine
for a moment a poorly trained, incompetent, or dishonest
laboratory analyst. (The analyst in Bullcoming, placed on
unpaid leave for unknown reasons, might qualify.) Under
our precedents, the prosecutor cannot avoid exposing that
analyst to cross-examination simply by introducing his
report. See Melendez-Diaz, 557 U. S., at 311. Nor can the
prosecutor escape that fate by offering the results through
the testimony of another analyst from the laboratory. See
Bullcoming, 564 U. S., at ___ (slip op., at 2). But under
the plurality’s approach, the prosecutor could choose the
analyst-witness of his dreams (as the judge here said, “the
best DNA witness I have ever heard”), offer her as an
expert (she knows nothing about the test, but boasts im-
pressive degrees), and have her provide testimony identi-
cal to the best the actual tester might have given (“the
DNA extracted from the vaginal swabs matched Sandy
Williams’s”)—all so long as a state evidence rule says that
                 Cite as: 567 U. S. ____ (2012)           17

                     KAGAN, J., dissenting

the purpose of the testimony is to enable the factfinder to
assess the expert opinion’s basis. (And this tactic would
not be confined to cases involving scientific evidence. As
JUSTICE THOMAS points out, the prosecutor could similarly
substitute experts for all kinds of people making out-of-
court statements. See ante, at 7.) The plurality thus
would countenance the Constitution’s circumvention. If
the Confrontation Clause prevents the State from getting
its evidence in through the front door, then the State could
sneak it in through the back. What a neat trick—but
really, what a way to run a criminal justice system. No
wonder five Justices reject it.
                              III
   The plurality also argues, as a “second, independent
basis” for its decision, that the Cellmark report falls out-
side the Confrontation Clause’s ambit because it is nontes-
timonial. Ante, at 3. The plurality tries out a number of
supporting theories, but all in vain: Each one either con-
flicts with this Court’s precedents or misconstrues this
case’s facts. JUSTICE THOMAS rejects the plurality’s views
for similar reasons as I do, thus bringing to five the num-
ber of Justices who repudiate the plurality’s understand-
ing of what statements count as testimonial. See ante, at
1, 12–15. JUSTICE THOMAS, however, offers a rationale
of his own for deciding that the Cellmark report is non-
testimonial. I think his essay works no better. When
all is said and done, the Cellmark report is a testimonial
statement.
                               A
   According to the plurality, we should declare the
Cellmark report nontestimonial because “the use at trial
of a DNA report prepared by a modern, accredited labora-
tory ‘bears little if any resemblance to the historical prac-
tices that the Confrontation Clause aimed to eliminate.’ ”
Ante, at 33 (quoting Michigan v. Bryant, 

___, ___
18                     WILLIAMS v. ILLINOIS

                         KAGAN, J., dissenting

(2011) (THOMAS, J., concurring in judgment) (slip op., at
2)). But we just last year treated as testimonial a forensic
report prepared by a “modern, accredited laboratory”;
indeed, we declared that the report at issue “fell within
the core class of testimonial statements” implicating the
Confrontation Clause. Bullcoming, 564 U. S., at ___ (slip
op., at 16) (internal quotation marks omitted); see Brief for
New Mexico Department of Health, Scientific Laboratory
Division as Amicus Curiae in Bullcoming, O. T. 2010, No.
09–10786, p. 1 (discussing accreditation). And although
the plurality is close, it is not quite ready (or able) to
dispense with that decision. See ante, at 29, n. 13 (“Expe-
rience might yet show that the holdings in [Bullcoming
and other post-Crawford] cases should be reconsidered”).
So the plurality must explain: What could support a dis-
tinction between the laboratory analysis there and the
DNA test in this case?4
  As its first stab, the plurality states that the Cellmark
report was “not prepared for the primary purpose of accus-
ing a targeted individual.” Ante, at 31. Where that test
comes from is anyone’s guess. JUSTICE THOMAS rightly
shows that it derives neither from the text nor from the
——————
   4 JUSTICE BREYER does not attempt to distinguish our precedents,

opting simply to adhere to “the dissenting view set forth in Melendez-
Diaz and Bullcoming.” See ante, at 8 (concurring opinion). He princi-
pally worries that under those cases, a State will have to call to the
witness stand “[s]ix to twelve or more technicians” who have worked on
a report. See ante, at 5; see also ante, at 3, 16–18. But none of our
cases—including this one—has presented the question of how many
analysts must testify about a given report. (That may suggest that in
most cases a lead analyst is readily identifiable.) The problem in the
cases—again, including this one—is that no analyst came forward to
testify. In the event that some future case presents the multiple-
technician issue, the Court can focus on “the broader ‘limits’ question”
that troubles JUSTICE BREYER, ante, at 7. But the mere existence of
that question is no reason to wrongly decide the case before us—which,
it bears repeating, involved the testimony of not twelve or six or three
or one, but zero Cellmark analysts.
                      Cite as: 567 U. S. ____ (2012)                     19

                          KAGAN, J., dissenting

history of the Confrontation Clause. See ante, at 14–15
(opinion concurring in judgment). And it has no basis in
our precedents. We have previously asked whether a
statement was made for the primary purpose of establish-
ing “past events potentially relevant to later criminal
prosecution”—in other words, for the purpose of providing
evidence. Davis, 547 U. S., at 822; see also Bullcoming,
564 U. S., at ___ (slip op., at 14); Bryant, 562 U. S., at ___,
___ (slip op., at 14, 29); Melendez-Diaz, 557 U. S., at 310–
311; Crawford, 541 U. S., at 51–52. None of our cases has
ever suggested that, in addition, the statement must be
meant to accuse a previously identified individual; indeed,
in Melendez-Diaz, we rejected a related argument that
laboratory “analysts are not subject to confrontation be-
cause they are not ‘accusatory’ witnesses.” 557 U. S., at
313.
   Nor does the plurality give any good reason for adopting
an “accusation” test. The plurality apparently agrees with
JUSTICE BREYER that prior to a suspect’s identification,
it will be “unlikely that a particular researcher has a
defendant-related motive to behave dishonestly.” Ante, at 12
(BREYER, J., concurring); see ante, at 31–32 (plurality
opinion). But surely the typical problem with laboratory
analyses—and the typical focus of cross-examination—has
to do with careless or incompetent work, rather than with
personal vendettas. And as to that predominant concern,
it makes not a whit of difference whether, at the time of
the laboratory test, the police already have a suspect.5
——————
  5 Neither can the plurality gain any purchase from the idea that a
DNA profile is not “inherently inculpatory” because it “tends to excul-
pate all but one of the more than 7 billion people in the world today.”
Ante, at 3; see ante, at 32. All evidence shares this feature: the more
inculpatory it is of a single person, the more exculpatory it is of the rest
of the world. The one is but the flipside of the other. But no one has
ever before suggested that this logical corollary provides a reason to
ignore the Constitution’s efforts to ensure the reliability of evidence.
20                   WILLIAMS v. ILLINOIS

                      KAGAN, J., dissenting

   The plurality next attempts to invoke our precedents
holding statements nontestimonial when made “to respond
to an ‘ongoing emergency,’ ” rather than to create evidence
for trial, Bryant, 562 U. S., at ___ (slip op., at 11); here, the
plurality insists, the Cellmark report’s purpose was “to
catch a dangerous rapist who was still at large.” Ante, at
31. But that is to stretch both our “ongoing emergency”
test and the facts of this case beyond all recognition. We
have previously invoked that test to allow statements by a
woman who was being assaulted and a man who had just
been shot. In doing so, we stressed the “informal [and]
harried” nature of the statements, Bryant, 562 U. S., at
___ (slip op., at 31)—that they were made as, or “minutes”
after, id., at ___ (slip op., at 28), the events they described
“actually happen[ed],” Davis, 547 U. S., at 827 (emphasis
deleted), by “frantic” victims of criminal attacks, ibid.,
to officers trying to figure out “what had . . . occurred” and
what threats remained, Bryant, 562 U. S., at ___ (slip op.,
at 30) (internal quotation marks omitted). On their face,
the decisions have nothing to say about laboratory ana-
lysts conducting routine tests far away from a crime scene.
And this case presents a peculiarly inapt set of facts
for extending those precedents. Lambatos testified at trial
that “all reports in this case were prepared for this crimi-
nal investigation . . . [a]nd for the purpose of the eventual
litigation,” App. 82—in other words, for the purpose of
producing evidence, not enabling emergency responders.
And that testimony fits the relevant timeline. The police
did not send the swabs to Cellmark until November
2008—nine months after L. J.’s rape—and did not receive
the results for another four months. See id., at 30–34, 51–
52, 54. That is hardly the typical emergency response.
   Finally, the plurality offers a host of reasons for why
reports like this one are reliable: “[T]here [i]s no prospect
of fabrication,” ante, at 31 (internal quotation marks
omitted); multiple technicians may “work on each DNA
                     Cite as: 567 U. S. ____ (2012)                   21

                         KAGAN, J., dissenting

profile,” ante, at 32; and “defects in a DNA profile may
often be detected from the profile itself,” ibid. See also
ante, at 10–14 (opinion of BREYER, J.). But once again:
Been there, done that. In Melendez-Diaz, this Court re-
jected identical arguments, noting extensive documenta-
tion of “[s]erious deficiencies . . . in the forensic evidence
used in criminal trials.” 557 U. S., at 319; see supra, at 4–
5; see also Bullcoming, 564 U. S., at ___, n. 1 (slip op., at 4,
n. 1) (citing similar errors in laboratory analysis); Brief for
Public Defender Service for the District of Columbia et al.
as Amici Curiae 13 (discussing “[s]ystemic problems,” such
as sample contamination, sample switching, mislabeling,
and fraud, at “ ‘flagship’ DNA labs”). Scientific testing is
“technical,” to be sure, ante, at 1 (opinion of BREYER, J.);
but it is only as reliable as the people who perform it.
That is why a defendant may wish to ask the analyst a
variety of questions: How much experience do you have?
Have you ever made mistakes in the past? Did you test
the right sample? Use the right procedures? Contaminate
the sample in any way? Indeed, as scientific evidence
plays a larger and larger role in criminal prosecutions,
those inquiries will often be the most important in the
case.6
——————
  6 Both  the plurality and JUSTICE BREYER warn that if we require ana-
lysts to testify, we will encourage prosecutors to forgo DNA evidence in
favor of less reliable eyewitness testimony and so “increase the risk of
convicting the innocent.” Ante, at 13 (BREYER, J., concurring); see ante,
at 3–4 (plurality opinion). Neither opinion provides any evidence, even
by way of anecdote, for that view, and I doubt any exists. DNA evi-
dence is usually the prosecutor’s most powerful weapon, and a prosecu-
tor is unlikely to relinquish it just because he must bring the right
analyst to the stand. Consider what Lambatos told the factfinder here:
The DNA in L. J.’s vaginal swabs matched Williams’s DNA and would
match only “1 in 8.7 quadrillion black, 1 in 390 quadrillion white, or
1 in 109 quadrillion Hispanic unrelated individuals.” App. 56–57. No
eyewitness testimony could replace that evidence. I note as well that
the Innocence Network—a group particularly knowledgeable about the
22                     WILLIAMS v. ILLINOIS

                         KAGAN, J., dissenting

   And Melendez-Diaz made yet a more fundamental point
in response to claims of the über alles reliability of scien-
tific evidence: It is not up to us to decide, ex ante, what
evidence is trustworthy and what is not. See 557 U. S., at
317–318; see also Bullcoming, 564 U. S., at ___ (slip op., at
11). That is because the Confrontation Clause prescribes
its own “procedure for determining the reliability of testi-
mony in criminal trials.” Crawford, 541 U. S., at 67. That
procedure is cross-examination. And “[d]ispensing with
[it] because testimony is obviously reliable is akin to dis-
pensing with jury trial because a defendant is obviously
guilty.” Id., at 62.
   So the plurality’s second basis for denying Williams’s
right of confrontation also fails. The plurality can find no
reason consistent with our precedents for treating the
Cellmark report as nontestimonial. That is because the
report is, in every conceivable respect, a statement meant
to serve as evidence in a potential criminal trial. And that
simple fact should be sufficient to resolve the question.
                             B
   JUSTICE THOMAS’s unique method of defining testimo-
nial statements fares no better. On his view, the Con-
frontation Clause “regulates only the use of statements
bearing ‘indicia of solemnity.’ ” Ante, at 8 (quoting Davis,
547 U. S., at 836–837). And Cellmark’s report, he con-
cludes, does not qualify because it is “neither a sworn nor a
certified declaration of fact.” Ante, at 9. But JUSTICE
THOMAS’s approach grants constitutional significance to
minutia, in a way that can only undermine the Confronta-
tion Clause’s protections.
——————
kinds of evidence that produce erroneous convictions—disagrees with
the plurality’s and JUSTICE BREYER’s view. It argues here that “[c]on-
frontation of the analyst . . . is essential to permit proper adversarial
testing” and so to decrease the risk of convicting the innocent. Brief
for the Innocence Network as Amicus Curiae 3, 7.
                 Cite as: 567 U. S. ____ (2012)           23

                     KAGAN, J., dissenting

   To see the point, start with precedent, because the
Court rejected this same kind of argument, as applied to
this same kind of document, at around this same time
just last year. In Bullcoming, the State asserted that
the forensic report at issue was nontestimonial because—
unlike the report in Melendez-Diaz—it was not sworn
before a notary public. We responded that applying the
Confrontation Clause only to a sworn forensic report
“would make the right to confrontation easily erasable”—
next time, the laboratory could file the selfsame report
without the oath. 564 U. S., at ___ (slip op., at 15). We
then held, as noted earlier, that “[i]n all material re-
spects,” the forensic report in Bullcoming matched the one
in Melendez-Diaz. 564 U. S., at ___ (slip op., at 15); see
supra, at 5. First, a law enforcement officer provided
evidence to a state laboratory assisting in police investiga-
tions. See 564 U. S., at ___ (slip op., at 15). Second, the
analyst tested the evidence and “prepared a certificate
concerning the result[s].” Ibid. Third, the certificate was
“formalized in a signed document . . . headed a ‘report.’ ”
Ibid. (some internal quotation marks omitted). That was
enough.
   Now compare that checklist of “material” features to the
report in this case. The only differences are that Cellmark
is a private laboratory under contract with the State
(which no one thinks relevant), and that the report is not
labeled a “certificate.” That amounts to (maybe) a nickel’s
worth of difference: The similarities in form, function, and
purpose dwarf the distinctions. See supra, at 5–6. Each
report is an official and signed record of laboratory test
results, meant to establish a certain set of facts in legal
proceedings. Neither looks any more “formal” than the
other; neither is any more formal than the other. See ibid.
The variances are no more (probably less) than would be
found if you compared different law schools’ transcripts
or different companies’ cash flow statements or different
24                     WILLIAMS v. ILLINOIS

                         KAGAN, J., dissenting

States’ birth certificates. The difference in labeling—a
“certificate” in one case, a “report of laboratory examina-
tion” in the other—is not of constitutional dimension.
   Indeed, JUSTICE THOMAS’s approach, if accepted, would
turn the Confrontation Clause into a constitutional gee-
gaw—nice for show, but of little value. The prosecution
could avoid its demands by using the right kind of forms
with the right kind of language. (It would not take long to
devise the magic words and rules—principally, never call
anything a “certificate.”)7 And still worse: The new con-
ventions, precisely by making out-of-court statements less
“solem[n],” ante, at 1, would also make them less relia-
ble—and so turn the Confrontation Clause upside down.
See Crawford, 541 U. S., at 52–53, n. 3 (“We find it im-
plausible that a provision which concededly condemned
trial by sworn ex parte affidavit thought trial by unsworn
ex parte affidavit perfectly OK”). It is not surprising that
no other Member of the Court has adopted this position.
To do so, as JUSTICE THOMAS rightly says of the plurality’s
decision, would be to “diminis[h] the Confrontation
Clause’s protection” in “the very cases in which the ac-
cused should ‘enjoy the right . . . to be confronted with the
witnesses against him.’ ” Ante, at 16.
                             IV
   Before today’s decision, a prosecutor wishing to admit
the results of forensic testing had to produce the techni-
cian responsible for the analysis. That was the result of
not one, but two decisions this Court issued in the last
three years. But that clear rule is clear no longer. The
five Justices who control the outcome of today’s case agree
——————
  7 JUSTICE THOMAS asserts there is no need to worry, because “the

Confrontation Clause reaches bad-faith attempts to evade the formal-
ized process.” Ante, at 10; see ante, at 9, n. 5. I hope he is right. But
JUSTICE THOMAS provides scant guidance on how to conduct this novel
inquiry into motive.
                 Cite as: 567 U. S. ____ (2012)          25

                     KAGAN, J., dissenting

on very little. Among them, though, they can boast of two
accomplishments. First, they have approved the introduc-
tion of testimony at Williams’s trial that the Confrontation
Clause, rightly understood, clearly prohibits. Second, they
have left significant confusion in their wake. What
comes out of four Justices’ desire to limit Melendez-Diaz
and Bullcoming in whatever way possible, combined with
one Justice’s one-justice view of those holdings, is—to be
frank—who knows what. Those decisions apparently no
longer mean all that they say. Yet no one can tell in what
way or to what extent they are altered because no pro-
posed limitation commands the support of a majority.
   The better course in this case would have been simply to
follow Melendez-Diaz and Bullcoming. Precedent-based
decisionmaking provides guidance to lower court judges
and predictability to litigating parties. Today’s plurality
and concurring opinions, and the uncertainty they sow,
bring into relief that judicial method’s virtues. I would
decide this case consistently with, and for the reasons
stated by, Melendez-Diaz and Bullcoming. And until a
majority of this Court reverses or confines those decisions,
I would understand them as continuing to govern, in every
particular, the admission of forensic evidence.
   I respectfully dissent.