In the

United States Court of Appeals
               For the Seventh Circuit

No. 10-3696

L INDA F LOREK,
                                                  Plaintiff-Appellant,
                                  v.

V ILLAGE OF M UNDELEIN , ILLINOIS, et al.,

                                               Defendants-Appellees.


             Appeal from the United States District Court
        for the Northern District of Illinois, Eastern Division.
         No. 05 cv 6402—Maria G. Valdez, Magistrate Judge.



       A RGUED JUNE 1, 2011—D ECIDED A UGUST 16, 2011




 Before F LAUM and S YKES, Circuit Judges, and C ONLEY,
District Judge. Œ
  F LAUM, Circuit Judge. When police searched her apart-
ment and placed her under arrest during a drug raid,
Linda Florek suffered a heart attack. She subsequently



Œ
  Hon. William M. Conley, Chief Judge of the Western District
of Wisconsin, sitting by designation.
2                                             No. 10-3696

filed suit in federal court, naming as defendants the
Village of Mundelein and several of its police officers.
Donovan Hansen is the only such officer who remains
in the case on appeal. Florek contends that police unrea-
sonably seized her within the meaning of the Fourth
Amendment by denying a request she made for baby
aspirin and refusing to call an ambulance for her. She
also maintains that police violated the Fourth Amend-
ment’s proscription against unreasonable searches by
not giving her sufficient time to answer the door when
they knocked and announced their presence prior to
entering her apartment. (After waiting 15 seconds, police
used a battering ram to gain entry.) On appeal, Florek
contests the summary judgment ruling that eliminated
one of her claims, the directed verdict ruling that elimi-
nated the Village from the case, and the in limine ruling
that barred one of her experts. We affirm.


                     I. Background
  In the fall of 2004, Village of Mundelein police offi-
cers using a confidential informant made two controlled
buys of marijuana at or in front of an apartment located
at 543 North Lake Street, in Mundelein. The apart-
ment was the residence of Linda Florek. Her son resided
there, too, and the person dealing drugs appears to
have been one of the son’s friends. Based on the con-
trolled buys, police obtained a search warrant for the
apartment. In the late evening hours of December 7, 2004,
several officers, led by then-Sergeant Donovan Hansen,
set out to execute the warrant.
No. 10-3696                                              3

   That night, Florek arrived home from work shortly
after 10:00 P.M . and settled in for the evening. She
changed into a T-shirt, retired to the living room, and
lit a marijuana cigarette. The last component of her eve-
ning’s activities was unfortunately timed, as illegality
literally lingered in the air when police executed their
search at 10:22 P.M . According to the defendants, the
search commenced when one of the officers knocked on
the door to Florek’s apartment and announced their
presence, stating, “Police department, search warrant.”
The officers then waited approximately 15 seconds
before breaching the door with a battering ram. Florek
disputes the contention that officers announced their
presence; all she heard were at least four impacts on
her door before officers entered the premises.
  As officers entered the apartment, Florek was standing
in the middle of the living room. She was ordered to the
ground and handcuffed. The apartment was redolent
of marijuana and, when asked about the odor, Florek
admitted that she threw a pouch of the substance
behind the couch as the officers had arrived. She ex-
plained that a physician had previously advised her
that she should smoke marijuana to reduce her blood
pressure. Regardless of the statement’s truth value, it
only bolstered the probable cause police had to arrest
her. See also Russell v. Harms, 

, 466 (7th Cir.
2005) (distinguishing Payton v. New York, 

(1980), and holding that police executing a lawful search
warrant may arrest a person inside the home, so long as
the arrest is founded on probable cause). During the
search, which lasted over an hour, Florek remained
4                                             No. 10-3696

handcuffed and was not allowed to change clothing.
Florek’s son was similarly restrained and brought into
the living room. The son was admonished by his mother
for inviting law enforcement attention by associating
with a drug dealer.
  Below (as on appeal), the chief dispute between the
parties centered around whether police officers were
unreasonable in responding to Florek’s medical needs.
Everyone agrees that early on during the execution of
the search warrant Florek asked if she could take some
baby aspirin. She made the request because roughly
two years earlier she had suffered a heart attack. The
paramedics who responded at that time had (among
other things) given her four baby aspirins. According to
Florek, the request for baby aspirin was denied outright.
She then told officers that she wanted an ambulance
because she was experiencing chest pains and having
a heart attack. In response, she was told that an am-
bulance would be called if she still needed one after
arriving at the police station.
  The defendants tell it differently. According to Hansen,
Florek did indeed ask for baby aspirin. He denied
the request, following the Village police department’s
general orders which require physicians to administer
medication. The relevant order also direct officers to
summon paramedics in the event of an emergency.
Hansen says he complied with the order, telling Florek
in response to her request for aspirin that he would call
for paramedics if she needed medical assistance. At
that point, Florek responded, “This is bullshit,” but did
No. 10-3696                                            5

not request an ambulance or let officers know she was
having chest pains. Hansen also says that Florek did not
appear to be under any more distress than would
have been expected under the circumstances. And al-
though she complained of shortness of breath at one
point, the problem was resolved when she com-
plied with Hansen’s admonition that she slow down
her breathing.
  The search was completed shortly after 11:30 P.M . At
around that time, Florek was allowed to get dressed,
and she and her son were transported to the Village’s
police station. The transport vehicle was a Chevy
cargo van equipped with interior partitions to separate
prisoners. While being placed in the van, Florek says
she pleaded, “Please don’t put me in that cage. I am
having a heart attack. I am claustrophobic.” The defen-
dants concede only that Florek protested the officers’
choice of vehicle, telling her that she would be trans-
ported in the vehicle despite her displeasure. The defen-
dants say that it was only after being placed in the van
that Florek informed officers of her chest pains. One of
the police officers, who was also a paramedic, spoke
with Florek while she was in the van. The officer
relayed what he learned to Hansen, the vehicle’s driver.
Hansen immediately radioed to have an ambulance
meet them at the station. The rendezvous occurred
within minutes.
  The night’s conclusion is subject to no real dispute.
The paramedics treated Florek. Then, after admin-
istering baby aspirin and nitroglycerine and running
6                                                No. 10-3696

an intravenous line, the paramedics took her to the hos-
pital. Hansen learned shortly thereafter that Florek had
suffered a heart attack. He dispatched two officers to
the hospital to complete Florek’s processing, which con-
sisted of fingerprinting and the posting of a recognizance
bond. (Hansen directed the officers to consult with
Florek’s treating physician to learn if there was a
medical reason not to finish the processing.) Florek was
charged with possessing less than 2.5 grams of mari-
juana. She received supervision and paid a fine.
  In November 2005, Florek filed suit in federal court.
The case was referred to a magistrate judge for all pur-
poses. See 28 U.S.C. § 636(c). The Village, Hansen, and
several police officers were named as defendants, but
Hansen is the only officer who remains. Just as the appeal
has brought into focus which parties are critical in the case,
it has winnowed the once-numerous claims. The ones
that matter for our purposes are Florek’s claims that
(1) Hansen and the Village unreasonably seized her
by denying her request for baby aspirin; (2) Hansen
unreasonably seized her by refusing to call an ambu-
lance when she first complained of chest pains; and
(3) Hansen effected an unreasonable search when the
officers he led failed properly to knock and announce
their presence and did not wait a reasonable time before
entering the apartment.
  Hansen and the Village moved for summary judgment.
The magistrate judge denied summary judgment on
Florek’s claim that Hansen unreasonably searched her
apartment because of his team’s alleged failure to properly
No. 10-3696                                               7

knock and announce its presence. The magistrate judge
noted that there were simply disputed facts about
whether police knocked, announced, and then waited a
reasonable time before entering. As to Florek’s claims
that the defendants unreasonably seized her by not re-
sponding reasonably to her medical needs, the magistrate
judge considered the claims separately. On the aspirin-
based claim, the magistrate judge granted summary
judgment on qualified immunity grounds, reasoning
that there was no clearly established right to over-the-
counter drugs during an arrest. Granting judgment to
the Village on that basis was not appropriate, see Owen
v. City of Independence, Missouri, 

, 638 (1980)
(holding that a “municipality may not assert the good
faith of its officers or agents as a defense to liability
under § 1983”), but Florek has not raised the error. (And
we shall see that the error was harmless, because there
was no constitutional violation.) In any event, the magis-
trate judge denied summary judgment on the ambulance-
based claim. That claim proceeded to trial, along with
the knock-and-announce claim.
  After the close of Florek’s case, the magistrate judge
granted the Village’s motion for a directed verdict, rea-
soning that Florek had not offered evidence sufficient
to impute liability to the Village under Monell v. Dep’t
of Soc. Servs. of the City of New York, 

(1978).
The jury considered only the two claims against Hansen;
brief deliberations produced a verdict in Hansen’s fa-
vor. Florek appeals.
8                                               No. 10-3696

                      II. Discussion
  On appeal, Florek takes no issue with the jury’s verdict
on the ambulance-based unreasonable seizure claim,
but does challenge the magistrate judge’s grant of sum-
mary judgment on the aspirin-based unreasonable sei-
zure claim. She also maintains that the directed verdict
in favor of the Village was improper, as was a decision
by the magistrate judge to bar an expert witness’s testi-
mony on the knock-and-announce claim. We take up,
and find wanting, each argument in turn.


A. Unreasonable Inattention to Medical Needs
  The Fourth Amendment to the United States Constitu-
tion provides: “The right of the people to be secure in
their persons, houses, papers, and effects, against unrea-
sonable searches and seizures, shall not be violated . . . .”
U.S. C ONST. amend. IV. We have held that an officer
violates the prohibition on unreasonable seizures when,
in the course of making an otherwise lawful arrest, he
does not respond reasonably to an arrestee’s medical
needs. Sides v. City of Champaign, 

, 828 (7th
Cir. 2007) (citing Graham v. Connor, 

, 394-95
(1989), and holding that the Fourth Amendment’s ban
on unreasonable seizures applies to claims of unrea-
sonable inattention to medical needs at the time of ar-
rest). Not every constitutional violation will furnish a
plaintiff with a basis for recovery, however. Qualified
immunity will shield an officer from money damages
unless a plaintiff establishes that the officer violated a
right that was clearly established. Pearson v. Callahan, 555
No. 10-3696                                               

, 231 (2009). And because “[l]evel of generality
is destiny” in law, see Thomas More Law Center v. Obama, ___
F.3d ___, 

, at *27 (6th Cir. June 29,
2011) (Sutton, J., concurring), it bears emphasizing
that courts should not decide that a right is clearly estab-
lished at a high level of abstraction: we look to “whether
the violative nature of particular conduct is clearly estab-
lished.” Ashcroft v. al-Kidd, 

, 2084 (2011)
(emphasis added).
   In this case, the magistrate judge determined that the
defendants enjoy qualified immunity with respect to
Hansen’s denial of Florek’s request for baby aspirin.
We review that determination de novo. Hill v. Cop-
pleson, 

, 605 (7th Cir. 2010). The analysis
comprises two questions (Pearson teaches that we may
take them up in any order; formerly we had to answer
them in sequence. See Saucier v. Katz, 

, 201
(2001)). First, we ask whether the plaintiff’s allegations
make out a deprivation of a constitutional right.
Second, we ask whether that right was clearly estab-
lished at the time of the defendant’s alleged misconduct.
Ault v. Speicher, 

, 945 (7th Cir. 2011). If
the answer to either question is no, the officer is
immune from suit. Here, the magistrate judge answered
no to the second question. We answer no to the first
question and hold that, as litigated by the parties, there
was no genuine issue of material fact on the claim
that police acted unreasonably by denying aspirin to
Florek.
  We say “as litigated by the parties,” because everyone
conceived of the case as having presented two discrete
10                                                  No. 10-3696

unreasonable seizure claims: (1) whether police acted
unreasonably by denying her request for baby aspirin,
an issue which dropped out of the case at summary
judgment; and (2) whether police acted unreasonably by
refusing to call an ambulance, an issue which went to
the jury and was resolved in Hansen’s favor. These con-
tentions ought to have been presented to the jury as a
single claim—namely, whether police violated Florek’s
constitutional rights by failing to respond reasonably to
her medical needs. After all, a claim is “the aggregate
of operative facts which give rise to a right enforceable
in the courts.” Original Ballet Russe v. Ballet Theater, 

, 189 (2d Cir. 1943) (Swan, J.); see also Liberty
Mutual Ins. Co. v. Wetzel, 

, 743 & n.4 (1976)
(intimating that a claim is a single legal theory “applied
to only one set of facts” but not “attempt[ing] any defini-
tive resolution of the meaning of what constitutes a
claim for relief within the meaning of the [Federal]
Rules”); Baltimore S.S. Co. v. Phillips, 

, 321 (1927)
(“A cause of action does not consist of facts, but of the
unlawful violation of a right which the facts show.”). And
because the reasonableness of a seizure depends on the
totality of the circumstances, see Tennessee v. Garner, 

, 8-9 (1985); Segura v. United States, 

,
806 (1984), determining whether police responded rea-
sonably to an arrestee’s medical needs demands the
same inquiry. In that vein, Williams v. Rodriguez, 

, 403 (7th Cir. 2007), distilled non-exclusive
factors that courts might look to in evaluating whether
a given police response was reasonable. Reasonableness
in light of the totality of the circumstances remains
No. 10-3696                                                11

the constitutional touchstone in this realm. See Lopez v.
City of Chicago, 

, 718 (7th Cir. 2006).
  If one concludes, as we have little difficulty doing
below, that police would have responded reasonably to
Florek’s medical needs by calling paramedics (the basis
of one “claim”)—regardless of whether she was allowed
to take aspirin (the basis of another “claim”)—it carries
the tacit acknowledgment that the “aggregate of opera-
tive facts” presented one claim all along. Cf. also Gen.
Acquisition, Inc. v. GenCorp., 

, 1029 (6th Cir.
1994) (discussing Federal Rule of Civil Procedure 54(b)).
Law enforcement addressing an arrestee’s medical needs
will either procure treatment, provide treatment, or
both. The circumstances should be considered together.
However, because the parties and magistrate judge de-
linked the issue of the treatment that Florek requested
from the steps that officers took in response to her
medical needs (and even on appeal Florek does not
claim that this was error), we will do the same.1


1
  The implication of the discussion above, however, is that
summary judgment should have been denied on a single
unreasonable inattention to medical needs claim, rather than
just denied with respect to an ambulance-based claim. Had
summary judgment been denied, Hansen’s refusal to pro-
vide aspirin would have been but one fact for the jury to
consider. How much and what type of evidence to present
on the denial-of-aspirin issue was a matter that would have
been within the sound discretion of the trial court. And in
the event the existence of a critical fact would have been
                                                (continued...)
12                                               No. 10-3696

Therefore, we ask only whether there was a genuine
issue of material fact on Florek’s unreasonable seizure
claim, assuming that officers called paramedics after
having been alerted to her chest pains.
  With that caveat, summary judgment was proper in
this case. The result is dictated by a straightforward
application of the factors we highlighted in Williams.
There, we identified four factors that courts might look
to in evaluating whether an officer’s response to an
arrestee’s medical needs was reasonable. The factors are
(1) “notice of the arrestee’s medical need . . . whether
by word . . . or through observation of the arrestee’s
physical symptoms”; (2) “the seriousness of the medical
need”; (3) “the scope of the requested treatment,” which
is balanced against the seriousness of the medical need;
and (4) police interests, a factor which “is wide-ranging
in scope and can include administrative, penological,
and investigatory concerns.” 

.
  One should not fixate on       factors, however: the intui-
tive, organizing principle is   that police must do more to
satisfy the reasonableness      inquiry when the medical
condition they confront is       apparent and serious and



1
   (...continued)
dispositive in the case—such as a timely call to paramedics—
a special verdict form could have been used to ensure the
proper outcome. On these facts, however, Florek should not
bemoan her loss at summary judgment. As explained below,
if police did promptly summon paramedics, they acted rea-
sonably in this case.
No. 10-3696                                            13

the interests of law enforcement in delaying treatment
are low. That is not the situation here. As to the first
factor, officers had knowledge of the request for baby
aspirin, but did not know that Florek was experiencing
chest pains, and her outward appearance did not put
officers on notice of her medical condition. (Again, the
way the parties presented the issue leads us to hold to
one side Florek’s contention that she did tell officers
she was experiencing chest pains and requested an am-
bulance.) Although her breathing was rapid at one
point, Hansen’s advice to take slower breaths appears
to have been effective. Moreover, Florek was conversing
at the scene, admonishing her son for his association
with a drug dealer. In short, law enforcement were not
on notice of a serious medical condition. The request
for baby aspirin was minor in scope as treatments go,
but the weight of this factor is substantially reduced by
the fact that the medical need did not appear to be
great. Our case law does not require police officers to
alleviate all discomfort or distress associated with ar-
rest. 

(“[T]he Constitution does
not require arrests to be conducted in comfort.”). As to
the fourth factor we identified in Williams, police had
a valid interest in denying the request for aspirin. Al-
though the police appear to have quickly brought the
arrest scene under control, they were executing a
search warrant for illegal narcotics, and they had no way
of knowing if a particular medication was in fact what
it purported to be. (The same conclusion might not
apply to an arrestee’s request to take prescription med-
ication in accordance with the instructions on the bottle,
14                                              No. 10-3696

as the containers for prescriptions describe the proper
appearance of the pill and the symptoms that trigger
their use.)
  Finally, and although we did not explicitly say as
much in Williams or in Sides, the Fourth Amendment
reasonableness inquiry necessarily takes into account
the sufficiency of the steps that officers did take. “Just
as the Fourth Amendment does not require a police
officer to use the least intrusive method of arrest,
neither does it require an officer to provide what
hindsight reveals to be the most effective medical care
for an arrested suspect.” Tatum v. City and County of
San Francisco, 

, 1098 (9th Cir. 2006) (citations
omitted); see also Jackson v. Kotter, 

, 697 (7th
Cir. 2008) (the Constitution is not a medical code re-
quiring officers to administer or allow specific treat-
ments); Forbes v. Edgar, 

, 267 (7th Cir. 1997)
(contrasting a reasonable response with a plaintiff’s
preferred response, in the context of an Eighth Amend-
ment claim). Here, we have assumed that an ambulance
was called promptly after officers were notified that
Florek was experiencing chest pains and wanted an
ambulance. That action will typically qualify as reason-
able. See 

(police acted reasonably
when they promptly summoned necessary medical assis-
tance, even if they did not administer CPR); see also
Sallenger v. City of Springfield, Illinois, 

, 504
(7th Cir. 2010) (police acted reasonably when they
promptly summoned necessary medical assistance and
administered CPR).
No. 10-3696                                                  15

  Florek points to no case where a court has held that
police acted unreasonably when they summoned emer-
gency medical personnel instead of supplying non-pre-
scription medication to an arrestee, nor has she pointed
to other authority that might help her in making the
argument. We located no helpful authority on her
behalf, and a straightforward application of our prece-
dent militates against her position. Thus, summary judg-
ment on the merits was appropriate as to Hansen, and
that means that judgment for the Village was proper as
well. 

(Monell liability cannot be
imposed where there is no underlying constitutional
violation).


B. The Village’s Motion for Directed Verdict
  We review de novo the magistrate judge’s decision to
grant the Village’s motion for a directed verdict—which
the Federal Rules of Civil Procedure refer to as judg-
ment as a matter of law. Freeman v. Madison Metro. Sch.
Dist., 

, 379 (7th Cir. 2000); Fed. R. Civ. P. 50(a).
“To avoid a directed verdict, the plaintiff must do more
than argue that the jury might have disbelieved all of the
defendant’s witnesses. Rather, the plaintiff must offer
substantial affirmative evidence to support her argu-
ment.” Heft v. Moore, 

, 284 (7th Cir. 2003).
   At the close of Florek’s case, the magistrate judge
granted the Village’s motion for a directed verdict, rea-
soning that the aspirin issue was no longer part of the
litigation and that Florek had not presented evidence
linking a municipal policy or custom to any constitutional
16                                              No. 10-3696

violation. On appeal, Florek concedes that a directed
verdict was proper as to all but the claim related to
aspirin. Having determined above that summary
judgment was appropriate on the denial of aspirin
issue, there remains no possible grounds for error.


C. Rulings on Expert Testimony
  Finally, Florek maintains that the magistrate judge
erred by barring expert testimony on whether police
acted unreasonably by waiting 15 seconds, after knocking
and announcing their presence, before ramming open
the door to her apartment. (She also contends that it
was error to bar expert testimony on the denial of
aspirin issue, but the issue was properly out of the case,
and so we need say no more.) The testimony in question
would have been offered by police expert Dennis
Waller. Waller would have testified that, given the late
hour at which the search was executed, “no rational,
experienced officer would/could reasonably expect a
response and voluntary compliance within fifteen sec-
onds” of knocking and announcing his presence. The
defendants’ motion in limine maintained that the
subject matter of Waller’s testimony was adequately
comprehensible by laypeople and therefore not
properly admissible as expert testimony. The magistrate
judge agreed.
  We review de novo whether the magistrate judge
“applied the appropriate legal standard in making its
decision to admit or exclude expert testimony, and we
review for abuse of discretion the . . . choice of factors to
No. 10-3696                                              17

include within that framework and . . . ultimate conclu-
sions regarding the admissibility of expert testimony.”
Happel v. Walmart Stores, Inc., 

, 824-25 (7th
Cir. 2010). Where the court below abuses its discretion
by keeping out evidence that ought to have been
admitted, a new trial will not be granted unless the omis-
sion of such evidence violated the party’s “substantial
rights.” Naeem v. McKesson Drug Co., 

, 608-09
(7th Cir. 2006); Fed. R. Civ. P. 61 (“At every stage of the
proceeding, the court must disregard all errors and de-
fects that do not affect any party’s substantial rights.”).
In order for expert testimony to be admissible, it must
satisfy the Federal Rule of Evidence’s threshold require-
ment that “specialized knowledge . . . assist the trier of
fact . . . to determine a fact in issue.” Fed. R. Evid. 702.
Once the threshold showing is made, experts may
provide assistance on a very great deal: an opinion is
not objectionable merely because “it embraces an
ultimate issue to be decided by the trier of fact.” Fed. R.
Evid. 704(a). Thus, there would be no problem with
Waller’s ultimate determination that police acted unrea-
sonably. The question is whether the basis of that deter-
mination—how long it takes for people to respond to
law enforcement’s knock at the door—was beyond the
ken of the average layperson. See 4 Jack B. Weinstein &
Margaret A. Berger, W EINSTEIN ’S F EDERAL E VIDENCE
¶ 702.03[1], at 702-34 (Matthew Bender 2d ed. 2011).
  Florek’s brief does not cite case law on when expert
testimony will help a jury determine whether police
conduct is reasonable. The case of Kopf v. Skyrm, 

(4th Cir. 1993), proves instructive. In Kopf, the Fourth
18                                                No. 10-3696

Circuit held that a district court abused its discretion in
excluding expert testimony about whether it was reason-
able for police to use a canine officer (and its canines) in
bringing a suspect to heel. The court noted that whether
force is excessive depends on the “objective reasonable-
ness” of the force used, a fact question. Yet, “any ‘objective’
test implies the existence of a standard of conduct, and,
where the standard is . . . defined by . . . the specific—
a reasonable officer—it is more likely that Rule 702’s line
between common and specialized knowledge has been
crossed.” 

In the context of the case, which
related to when police officers will find it necessary to
use police dogs and certain specialized devices in
gaining control over a suspect, the court ruled that the
line had been crossed. However, the court noted that
expert testimony might not be helpful in other situations,
such as where police used their bare hands in making
an arrest, the “most primitive form” of force. 

In other words, expert testimony is more likely to
satisfy Federal Rule of Evidence 702’s requirement that
it “assist the trier of fact to understand the evidence
or determine a fact in issue” when something peculiar
about law enforcement (e.g., the tools they use or the
circumstances they face) informs the issues to be
decided by the finder of fact. See United States v. Shedlock,

, 219 (8th Cir. 1995). Of course, that does not
mean that expert testimony can war with the pertinent
legal standards at play. Cf. Whren v. United States, 

, 815 (1996) (noting that certain police practices
“vary from place to place and from time to time” and
rejecting the view that constitutional protections are “so
variable”). And when the testimony is about a matter of
No. 10-3696                                                19

everyday experience, expert testimony is less likely to be
admissible. United States v. Hanna, 

, 1085-86
(9th Cir. 2002) (testimony of Secret Service agents on
whether a reasonable person in the defendant’s position
would foresee that communications would be perceived
as threatening the President was not beyond the under-
standing of the average layperson); Beck v. City of Pitts-
burgh, 

, 975-76 (3d Cir. 1996).
  Measuring Waller’s testimony against these standards,
there can be no doubt that the magistrate judge
properly exercised her discretion in barring Waller’s
testimony. The knock-and-announce rule about which
Waller would have opined is a factor to be considered
when evaluating the reasonableness of a search. See
Wilson v. Arkansas, 

, 934 (1995). Informed
by principles of English common law, 

the
Court in Wilson held that the Fourth Amendment gen-
erally requires police, before forcibly entering someone’s
home, to seek voluntary compliance with a lawful war-
rant by knocking and announcing their presence, 

Despite the general rule, the Court noted that
law enforcement interests may militate in favor of dis-
pensing with it in certain circumstances. The Court high-
lighted concerns over destruction of evidence and
danger faced by police officers in particular, but other-
wise left it to lower courts to develop the law in this
realm. 

2
  Generally, we have refused to turn the knock-and-announce
rule “into a constitutional stop-watch where a fraction of a
                                                (continued...)
20                                                   No. 10-3696

  Plainly, the concerns highlighted by the Court will
inform the determination about whether law enforce-
ment have waited a reasonable time before gaining
entry to a residence by force. It is self-evident that expert
testimony may be useful on those subjects. How long
does it take to dispose of drugs? What sorts of prob-
lems do law enforcement encounter the longer they wait
before entering a residence? These are questions whose
answers cannot be furnished by everyday experience.
Waller’s testimony, on the other hand, did not ap-
proach Rule 702 territory. It appears that Waller’s chief
contribution was going to be his belief that, given the
late hour, it would have been unreasonable to expect
voluntary compliance with a knock at the door in
15 seconds. Florek does not explain why expert testi-
mony on this subject would be useful to the jury, instead
seeming to contend that expert testimony is always
necessary where “constitutional freedoms and guarantees
are concerned” and police practices are at issue. That
position is untenable; everyday experience teaches



2
  (...continued)
second assumes controlling significance.” United States v.
Espinoza, 

, 722 (7th Cir. 2001). What is reasonable
must be determined “under the particular factual situation
presented.” Id.; see also United States v. Jones, 

, 610
(7th Cir. 2000) (upholding district court’s determination that
5 to 13 seconds was reasonable where police had concerns
that a suspect was armed and also “a lengthy period of time
would give the defendant an opportunity to destroy the drug
evidence”).
No. 10-3696                                         21

people how long it takes to walk from room to room.
The magistrate judge did not abuse her discretion in
barring the testimony, nor did she do so by keeping
out Waller’s testimony that a reasonable police officer
would call an ambulance if confronted with an arrestee
known to be experiencing heart attack symptoms.


                   III. Conclusion
  For the reasons set forth above, the judgment of the
district court is A FFIRMED.




                        8-16-11