FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

ANTHONY TOMMASETTI,                        
               Plaintiff-Appellant,               No. 06-55999
               v.
                                                   D.C. No.
                                                CV-04-09812-PJW
MICHAEL J. ASTRUE,*
Commissioner of Social Security,                   OPINION
              Defendant-Appellee.
                                           
         Appeal from the United States District Court
              for the Central District of California
         Patrick J. Walsh, Magistrate Judge, Presiding

                    Argued and Submitted
           February 15, 2008—Pasadena, California

                        Filed July 17, 2008

       Before: Stephen S. Trott, Richard R. Clifton, and
            Consuelo M. Callahan, Circuit Judges.

                   Opinion by Judge Callahan




  *Michael J. Astrue is substituted for his predecessor Jo Anne Barnhart
as Commissioner of the Social Security Administration. Fed. R. App. P.
43(c)(2).

                                 8827
8830              TOMMASETTI v. ASTRUE


                      COUNSEL

Young Cho, Esq., Law Offices of Lawrence D. Rohlfing
Attorneys At Law, for plaintiff-appellant Anthony Tomma-
setti.
                     TOMMASETTI v. ASTRUE                  8831
Peter D. Keisler, Assistant Attorney General, George S. Car-
dona, Acting United States Attorney, Lucille Gonzales Meis,
Regional Chief Counsel, Region IX, and Geralyn A. Gulseth
(Argued), Special Assistant U.S. Attorney, for defendant-
appellee Michael J. Astrue, Commissioner of Social Security.


                          OPINION

CALLAHAN, Circuit Judge:

   Anthony Tommasetti (“Tommasetti”) filed an application
for Social Security benefits claiming that he was unable to
work because of lower back pain and diabetes mellitus. After
an initial denial of that application, and following what the
district court characterized as an “administrative odyssey,” the
Social Security Appeals Council remanded Tommasetti’s
claim to a new Administrative Law Judge (“ALJ”) to conduct
a de novo hearing. At that hearing, the ALJ took testimony
from a medical expert, a vocational expert (“VE”), and Tom-
masetti. After largely rejecting the opinion of one of Tomma-
setti’s treating physicians and finding Tommasetti’s testimony
not credible, the ALJ concluded, based almost entirely on the
VE’s testimony, that Tommasetti could perform his past
work. Alternatively, the ALJ found that Tommasetti could
perform other work in the national economy and local econ-
omy. The Appeals Council declined jurisdiction over Tomma-
setti’s appeal, and the district court affirmed the ALJ’s
decision as supported by substantial evidence.

   We hold that the ALJ provided “clear and convincing” rea-
sons for rejecting Tommasetti’s testimony as not credible. See
Smolen v. Chater, 

, 1283-84 (9th Cir. 1996). We
further conclude that the ALJ provided “specific and legiti-
mate” reasons based on substantial evidence for her partial
rejection of the treating physician’s opinion. See Lester v.
Chater, 

, 830-31 (9th Cir. 1995). Finally, we hold
8832                      TOMMASETTI v. ASTRUE
that although the ALJ erred in finding that Tommasetti could
perform past work, see Johnson v. Shalala, 

,
1434-35 (9th Cir. 1995), this error was harmless because the
ALJ properly decided that Tommasetti could perform other
work in the economy. See Robbins v. Soc. Sec. Admin., 

, 885 (9th Cir. 2006). Accordingly, we affirm the dis-
trict court’s decision.

                            I.   Background

A.     Tommasetti’s Relevant Personal and Medical History

   Tommasetti was 53 years old on the alleged date of onset
of his medical conditions at issue here, and he was 59 years
old when his disability insurance expired in December 1999.
Tommasetti attended college in Italy, has training in electron-
ics, and previously worked as an electronics technician and
TV repair person. He was involved in a car accident in April
1994 and was in pain until October 1994. Later that year he
fell off a ladder while working. He was involved in subse-
quent car accidents in 1999 and 2000.

   While Tommasetti saw several physicians, at issue on
appeal is Dr. Andrea Nachenberg’s reports based on her inter-
mittent treatment of Tommasetti.1 Dr. Nachenberg first saw
Tommasetti in March 1995, at which time she noted his
claims of back pain and inability to stay in one position for
more than ten minutes. Upon conducting a physical exam she
noted “no evidence of weakness” and “minimal tenderness”
on palpation. She diagnosed a “probable lumbosacral strain
superimposed on osteoarthritis of the lumbar spine.” She saw
him again in July 1996 for right shoulder and right knee pain,
and in October 1996 for lower back pain. An x-ray of his back
revealed spurring and narrowing of the L4-5 and L5-S1 inter-
spaces. Tommasetti again saw Dr. Nachenberg in March 1997
and November 1997 about lower back pain. In December
  1
     Dr. Nachenberg did not testify at the administrative hearing.
                    TOMMASETTI v. ASTRUE                  8833
1997, Dr. Nachenberg wrote a letter that summarized Tomma-
setti’s medical history and concluded that she did “not expect
him to recover significantly at this time.” Dr. Nachenberg
next saw Tommasetti in September 1998 and completed a
“Musculoskeletal System Residual Functional Capacity Ques-
tionnaire” (“Questionnaire”). She stated that Tommasetti
could sit continuously for ten minutes, and for up to four
hours in an eight-hour workday; stand continuously for thirty
minutes, and for up to two hours in an eight-hour workday;
required use of a lumbosacral corset; and could at most occa-
sionally lift ten pounds.

B.   Hearing Testimony

   Tommasetti testified at the hearing before the ALJ regard-
ing his lower back pain and diabetes. He testified that he
could not stand, walk, climb ladders, or work; but that he
could have a job where he was on his feet for no more than
two hours a day, without ladder-climbing. He claimed that at
the time in question he could lift at most a few pounds. He
also stated that he stopped taking prescribed medicine in 1995
or 1996 due to dizziness, and he could not recall if a doctor
had prescribed the walking cane he intermittently used. He
further testified that he had made no attempts to work and that
he supported himself with $97,000 in savings. Contrary to
previous representations, Tommasetti testified that diabetes
was not a disabling problem and that medication properly
controlled it.

  At the hearing, the ALJ took testimony from Dr. Wiseman,
an agency medical expert who testified based on his review
of Tommasetti’s medical records. The ALJ found Dr. Wise-
man’s testimony to be “somewhat equivocal.” Although Dr.
Wiseman opined that Tommasetti had elected to limit himself
based on self-chosen limitations, he refused to definitively
assess Tommasetti’s condition. Instead, he merely “accepted”
what Dr. Nachenberg stated. He did not, however, explicitly
endorse Dr. Nachenberg’s assessment.
8834                   TOMMASETTI v. ASTRUE
   The VE testified regarding Tommasetti’s ability to perform
his prior work and other work in the national economy and
local economy. The VE noted that Tommasetti previously
worked in electronics assembly and TV repair. The VE
responded to hypothetical questions based on the following
residual functioning capacity: capable of lifting up to ten
pounds, standing or walking for six hours in an eight-hour
workday (in two-hour increments), and sitting for six hours in
an eight-hour workday. Regarding prior work as an electron-
ics assembler, the VE opined that Tommasetti could not per-
form that work as he had previously performed it, but
concluded without much elaboration that he could perform it
as it is “typically performed.” The VE also testified that Tom-
masetti could perform work in the national economy as a
semiconductor assembler, for which there were 100,000 jobs
nationally and 9,000 jobs regionally.

                 II.    Standards of Review

   We review the district court’s order affirming the ALJ’s
denial of social security benefits de novo, Burch v. Barnhart,

, 679 (9th Cir. 2005), and will disturb the denial
of benefits only if the decision “contains legal error or is not
supported by substantial evidence.” Orn v. Astrue, 

, 630 (9th Cir. 2007) (citation omitted). Substantial evi-
dence is “ ‘such relevant evidence as a reasonable mind might
accept as adequate to support a conclusion.’ ” 

400 F.3d at 679). The “evidence must be more than a
mere scintilla but not necessarily a preponderance.” Connett
v. Barnhart, 

, 873 (9th Cir. 2003) (citation omit-
ted). The ALJ’s findings will be upheld “if supported by
inferences reasonably drawn from the record . . . .” Batson v.
Comm’r of Soc. Sec. Admin., 

, 1193 (9th Cir.
2004). The court will uphold the ALJ’s conclusion when the
evidence is susceptible to more than one rational interpreta-
tion. 

; 

.
Finally, the court will not reverse an ALJ’s decision for harm-
less error, which exists when it is clear from the record that
                     TOMMASETTI v. ASTRUE                  8835
“the ALJ’s error was ‘inconsequential to the ultimate nondisa-
bility determination.’ ” 

(quoting
Stout v. Comm’r, Soc. Sec. Admin., 

, 1055-56
(9th Cir. 2006)).

                       III.   Discussion

   The ALJ used the required five-step sequential framework
to determine whether Tommasetti was disabled. See 20 C.F.R.
§ 404.1520; see also 

. At step one, the
ALJ found that Tommasetti had not engaged in substantial
gainful activity during the relevant period. At step two, the
ALJ concluded that Tommasetti “satisfied the threshold or de
minimus step of having a severe impairment” by reason of his
lumbosacral condition and diabetes mellitus. At step three, the
ALJ found that Tommasetti’s back condition and diabetes did
not meet or equal one of the listed impairments in the regula-
tions. At step four, based on the residual functional capacity
determination and the VE’s testimony, the ALJ concluded
that Tommasetti was able to perform past relevant work as an
electronics assembler. However, acknowledging “confusion
in the analysis of past relevant work” and her hesitation “to
play expert,” the ALJ made an alternative step five finding
that, assuming Tommasetti could not perform past work, he
could still perform other work in the national or local econ-
omy as a semiconductor assembler.

A.   Adverse Credibility Determination

   Tommasetti argues that the ALJ’s adverse credibility find-
ing is not supported by the record. In order to find Tommaset-
ti’s testimony regarding the severity of his pain and
impairments unreliable, the ALJ was required to make “a
credibility determination with findings sufficiently specific to
permit the court to conclude that the ALJ did not arbitrarily
discredit claimant’s testimony.” Thomas v. Barnhart, 

, 958 (9th Cir. 2002). The ALJ conducts a two-step
analysis to assess subjective testimony where, under step one,
8836                 TOMMASETTI v. ASTRUE
the claimant “must produce objective medical evidence of an
underlying impairment” or impairments that could reasonably
be expected to produce some degree of symptom. 

. If the claimant meets this threshold and there
is no affirmative evidence of malingering, “the ALJ can reject
the claimant’s testimony about the severity of her symptoms
only by offering specific, clear and convincing reasons for
doing so.” 

1283-84. The ALJ may consider many
factors in weighing a claimant’s credibility, including “(1)
ordinary techniques of credibility evaluation, such as the
claimant’s reputation for lying, prior inconsistent statements
concerning the symptoms, and other testimony by the claim-
ant that appears less than candid; (2) unexplained or inade-
quately explained failure to seek treatment or to follow a
prescribed course of treatment; and (3) the claimant’s daily
activities.” 

see 

. If the
ALJ’s finding is supported by substantial evidence, the court
“may not engage in second-guessing.” 

.

   [1] Here, the ALJ gave Tommasetti “the benefit of the
doubt” that he had a verifiable impairment and, therefore, the
ALJ was required to provide clear and convincing reasons in
support of her adverse credibility finding. The ALJ provided
several permissible reasons. First, she inferred that Tomma-
setti’s pain was not as all-disabling as he reported in light of
the fact that he did not seek an aggressive treatment program
and did not seek an alternative or more-tailored treatment pro-
gram after he stopped taking an effective medication due to
mild side effects. This is a permissible inference. See Parra
v. Astrue, 

, 750-51 (9th Cir. 2007) (stating that
“evidence of ‘conservative treatment’ is sufficient to discount
a claimant’s testimony regarding severity of an impairment”);
see also Meanel v. Apfel, 

, 1114 (9th Cir. 1999)
(rejecting subjective pain complaints where petitioner’s
“claim that she experienced pain approaching the highest
level imaginable was inconsistent with the ‘minimal, conser-
                         TOMMASETTI v. ASTRUE                         8837
vative treatment’ that she received”).2 The record reflects that
Tommasetti responded favorably to conservative treatment
including physical therapy and the use of anti-inflammatory
medication, a transcutaneous electrical nerve stimulation unit,
and a lumbosacral corset. Such a response to conservative
treatment undermines Tommasetti’s reports regarding the dis-
abling nature of his pain.

   [2] Second, the ALJ cited that Tommasetti was a “vague
witness” with respect to the alleged period of disability and
pain symptoms. The ALJ may rely on ordinary techniques of
credibility evaluation. 

. The record
supports the ALJ’s determinations that on questioning Tom-
masetti “was not clear or certain insofar as his self-assessed
work capabilities,” and that he was not “a precise judge of his
own capacities.” She further commented that Tommasetti had
made no attempts to perform sedentary work and had pro-
vided only a vague explanation as to why: “Because I cooked.
I would feel good.” The ALJ also noted that Tommasetti
could not recall whether the cane he occasionally used was
prescribed by a doctor.

   [3] Third, the ALJ pointed to Tommasetti’s testimony that
his severe diabetes was not a “disabling problem,” was con-
trolled by medication, and was not the reason he stopped
working. This testimony undermines Tommasetti’s prior
claims that his diabetes was among his disabling conditions.
See 

.
  2
    Tommasetti testified that his doctors suggested back surgery, but that
he did not want to risk the procedure. Although not expressly relied on by
the ALJ, the district court contrasted Tommasetti’s reluctance to undergo
back surgery to possibly end his debilitating pain with his willingness to
risk an invasive elective surgery that would correct a largely cosmetic uro-
logical condition. Because the ALJ did not rely on this reason in support
of her credibility determination, we may not rely upon it here. See Con-

(“We are constrained to review the reasons the ALJ
asserts.”).
8838                    TOMMASETTI v. ASTRUE
   [4] Fourth, the ALJ stated that regarding the period in ques-
tion Tommasetti “may not have been motivated to work due
to his then large financial reserve.” Although some might not
consider $97,000 to be a large financial reserve, we cannot
say that the ALJ’s inference regarding Tommasetti’s motiva-
tion to work based on this savings was unreasonable. See
Sample v. Schweiker, 

, 642 (9th Cir. 1982) (stat-
ing that in reaching findings the ALJ “is entitled to draw
inferences logically flowing from the evidence”).

   [5] Finally, the ALJ doubted Tommasetti’s testimony about
the extent of his pain and limitations based on his ability to
travel to Venezuela for an extended time to care for an ailing
sister. The ALJ could properly infer from this fact that Tom-
masetti was not as physically limited as he purported to be. Id.3

   [6] The ALJ’s reasons for discounting Tommasetti’s testi-
mony are supported by substantial evidence in the record.
Accordingly, we will not disturb the ALJ’s adverse credibility
finding.

B.     Rejection of Dr. Nachenberg’s Opinion

   [7] Tommasetti next argues that the ALJ improperly dis-
counted the opinion of his treating physician, Dr. Andrea
Nachenberg, regarding Tommasetti’s physical limitations. Dr.
Nachenberg completed the Questionnaire, in which she
opined that Tommasetti could sit continuously for ten min-
utes, sit for four hours in an eight-hour workday, stand contin-
uously for thirty minutes, stand/walk for two hours in an
eight-hour workday, required an ability to sit and stand at
will, needed unscheduled breaks, and could at most occasion-
ally lift ten pounds. The ALJ rejected Dr. Nachenberg’s opin-
ion only to the limited extent that it ruled out Tommasetti’s
“capacity for sedentary work” during the period in question.
  3
   Although Tommasetti raises the fact that he had to see a physician for
exacerbation of his back pain while in Venezuela, the physician only con-
sidered Tommasetti “unable to do strong physical work.”
                     TOMMASETTI v. ASTRUE                   8839
   The ALJ must consider all medical opinion evidence. 20
C.F.R. § 404.1527(b). Although the ALJ is not bound by an
expert medical opinion on the ultimate question of disability,
she must provide “specific and legitimate” reasons for reject-
ing the opinion of a treating physician. 

-
31. “The ALJ can meet this burden by setting out a detailed
and thorough summary of the facts and conflicting clinical
evidence, stating [her] interpretation thereof, and making
findings.” Magallanes v. Bowen, 

, 751 (9th Cir.
1989) (citation omitted).

    [8] The ALJ complied with Magallanes and provided spe-
cific and legitimate reasons for rejecting Dr. Nachenberg’s
opinion that are supported by the entire record. The ALJ
stated that Dr. Nachenberg’s assessment was essentially a “re-
hashing of claimant’s own statements,” and was therefore
undermined by the ALJ’s finding that Tommasetti was not
credible. An ALJ may reject a treating physician’s opinion if
it is based “to a large extent” on a claimant’s self-reports that
have been properly discounted as incredible. Morgan v.
Comm’r Soc. Sec. Admin., 

, 602 (9th Cir. 1999)
(citing Fair v. Bowen, 

, 605 (9th Cir. 1989)). A
review of Dr. Nachenberg’s records reveals that they largely
reflect Tommasetti’s reports of pain, with little independent
analysis or diagnosis. Additionally, Dr. Wiseman, the consult-
ing medical expert, testified that Dr. Nachenberg’s Question-
naire primarily reflected Tommasetti’s self-assessment and
subjective willingness to work. Thus, the ALJ’s adverse credi-
bility determination supports the limited rejection of Dr. Nac-
henberg’s opinion because it was primarily based on
Tommasetti’s subjective comments concerning his condition.

   [9] Further, after discussing Tommasetti’s medical history
and treatments in detail, the ALJ found that Dr. Nachenberg’s
Questionnaire responses were inconsistent with the medical
records. For example, the ALJ stated that the ultimate conclu-
sions from Dr. Nachenberg’s Questionnaire regarding the
extent of Tommasetti’s ability to stand and sit and his need
8840                TOMMASETTI v. ASTRUE
for breaks “did not mesh with her objective data or history.”
Indeed, Dr. Nachenberg’s medical records do not provide sup-
port for the limitations set out in the Questionnaire. The
incongruity between Dr. Nachenberg’s Questionnaire
responses and her medical records provides an additional spe-
cific and legitimate reason for rejecting Dr. Nachenberg’s
opinion of Tommasetti’s limitations.

   [10] Tommasetti contends that Dr. Wiseman’s “deferral” to
Dr. Nachenberg’s assessment weighs against the ALJ’s rejec-
tion of Dr. Nachenberg’s opinion. Although Dr. Wiseman
“accepted” Dr. Nachenberg’s opinion, Dr. Wiseman simulta-
neously concluded that Dr. Nachenberg’s opinion was based
on Tommasetti’s self-reporting and expressed doubts as to
Tommasetti’s limitations. He also refused to provide a defi-
nite opinion of Tommasetti’s condition or limitations. Dr.
Wiseman’s testimony, although equivocal, did not amount to
a concurrence in Dr. Nachenberg’s opinion but only indicated
that he accepted her opinion because she was a qualified phy-
sician. In any event, the ALJ is the final arbiter with respect
to resolving ambiguities in the medical evidence. See
Andrews v. Shalala, 

, 1039-40 (9th Cir. 1995)
(“The ALJ is responsible for determining credibility, resolv-
ing conflicts in medical testimony, and for resolving ambigui-
ties.”) (citing 

). On this record,
the ALJ reasonably rejected Dr. Nachenberg’s opinion to the
extent that it precluded Tommasetti from performing seden-
tary work.

C.     Tommasetti’s Ability to Perform Past Work and
       Other Work

   [11] Tommasetti further argues that the ALJ committed
error at step four by finding that he could have returned to
past work as an electronics assembler. The ALJ determined
that Tommasetti’s physical impairment limited him to “seden-
tary work,” with a maximum lifting capacity of ten pounds.
At step four, the ALJ and VE agreed that, based on the elec-
                     TOMMASETTI v. ASTRUE                    8841
tronics assembler job classification in the Dictionary of Occu-
pational Titles (“DOT”), Tommasetti could not perform
electronics assembly work as he actually performed it because
it would require him to lift more than ten pounds. However,
the VE testified that electronics assembly work is performed
in a variety of ways in the national economy. The ALJ
deferred to the VE’s assessment, stating that “regardless of
the differences in demands in the position as performed in the
national economy, it would not ordinarily require that the
individual perform activities requiring a greater residual func-
tional capacity” than that of Tommasetti.

   [12] This assessment is contrary to the ALJ’s determination
that Tommasetti could only perform “sedentary” work
because the DOT lists the “electronics assembler” position as
requiring “light” exertion. Dictionary of Occupational Titles
§ 726.684-018 (4th ed. 1991); see 20 C.F.R. § 404.1567(a),
(b). The DOT creates a rebuttable presumption as to the job
classification. 

. To deviate from the
DOT classification, an ALJ “may rely on expert testimony
which contradicts the DOT, but only insofar as the record
contains persuasive evidence to support the deviation.” 

ALJ offered her own speculative explanation to
rebut the DOT’s presumptive exertion requirement, comment-
ing that the reason for the light exertion label is that the posi-
tion “may require some pushing or pulling of arm controls.”
She concluded that this requirement should not elevate the job
classification from sedentary to light. The ALJ also deferred
to the VE’s personal knowledge and experience as supersed-
ing the DOT to the extent that the light exertion label was
related to any standing/walking requirements.

   [13] The ALJ’s determination that Tommasetti could return
to his work as an electronics assembler is not supported by the
record. Instead of persuasive evidence in the record, the ALJ
relied on her own speculation and the VE’s brief and indefi-
nite testimony. Id.; Soc. Sec. Ruling 00-4p (Dec. 4, 2000)
(stating that “[t]he adjudicator must resolve the conflict by
8842                     TOMMASETTI v. ASTRUE
determining if the explanation given by the VE or [vocational
specialist] is reasonable and provides a basis for relying on
the VE or [vocational specialist] testimony rather than on the
DOT information”). The ALJ did not identify what aspect of
the VE’s experience warranted deviation from the DOT, and
did not point to any evidence in the record other than the VE’s
sparse testimony for the deviation. Therefore, the ALJ’s step
four finding was erroneous.

   [14] Although the ALJ’s step four determination constitutes
error, it is harmless error in light of the ALJ’s alternative find-
ing at step five. At step five, the ALJ concluded that, assum-
ing Tommasetti could not perform past work, he could still
perform other work in the national and local economies that
existed in significant numbers. 20 C.F.R. §§ 404.1520(a)
(4)(v), 404.1560(c); 

(holding that
error that is inconsequential to the ultimate nondisability
determination is harmless error). The ALJ, relying on the
VE’s testimony, found that Tommasetti could work as a semi-
conductor assembler, which is a sedentary, semi-skilled posi-
tion offering 100,000 positions nationally and 9,000
regionally. See Dictionary of Occupational Titles § 726.684-
034. The VE testified that Tommasetti’s prior skills as an
electronics assembler transferred to the “very closely related”
semiconductor assembler job because both positions involve
similar assembler tools, assembler products, and sub-
assembly components, and the semiconductor assembler posi-
tion simply involves smaller items.

   [15] The ALJ also found that the VE’s testimony aug-
mented Rule 201.07 of the Medical Vocational Guidelines
(the “grids”), 20 C.F.R. Part 404, Subpart P, Appendix 2,4
  4
    We summarized the role of the grids, in the evaluation of a disability
claim in Lounsburry v. Barnhart, 

, 1114-15 (9th Cir. 2006):
      The grids are applied at the fifth step of the analysis under 20
      C.F.R. § 404.1520, and present, in table form, a short-hand
                       TOMMASETTI v. ASTRUE                         8843
which provides an alternate basis for finding that Tommasetti
was not disabled. Pursuant to Rule 201.07, a claimant of
advanced age who is limited to sedentary work, has a high
school degree, can perform skilled or semi-skilled work, and
has transferrable skills is “not disabled.” Rule 201.07 is aug-
mented by Rule 201.00(f), which states that “[i]n order to find
transferability of skills to skilled sedentary work for individu-
als who are of advanced age . . . , there must be very little,
if any, vocational adjustment required in terms of tools, work
processes, work settings, or the industry.” Tommasetti meets
these criteria.

   Tommasetti argues that the ALJ’s step five determination
is undermined by this court’s decision in Lounsburry v. Barn-
hart, 

(9th Cir. 2006), which was filed after the
district court’s decision in this case. In Lounsburry, the claim-
ant was restricted to performing light work and had transferr-
able skills. 

The court found that Rule 202.07,
from the grid table governing light exertion, applied and that
Footnote 2 to Rule 202.07 expressly incorporated language
from Rule 202.00(c). 

of this incorporation was
that a person of advanced age with a high school degree who
could do light work could only be found “not disabled” if her
skills were readily transferable to a “significant range” of

   method for determining the availability and numbers of suitable
   jobs for a claimant. [Tackett v. Apfel, 

, 1101 (9th
   Cir. 1999).] The grids categorize jobs by their physical-exertional
   requirements, and set forth a table for each category. A claim-
   ant’s placement with the appropriate table is determined by
   applying a matrix of four factors identified by Congress—a
   claimant’s age, education, previous work experience, and physi-
   cal ability. For each combination of these factors, they direct a
   finding of either “disabled” or “not disabled” based on the num-
   ber of jobs in the national economy in that category of physical-
   exertional requirements. 

claimant is found able to work
   jobs that exist in significant numbers, the claimant is generally
   considered not disabled. Heckler v. Campbell, 

, 461
   . . . (1983).
8844                   TOMMASETTI v. ASTRUE
semi-skilled or skilled work. 

The court held
that one “occupation” did not constitute a “significant range”
and, because the ALJ had only identified one occupation,
Lounsburry was “disabled.” 

   [16] Tommasetti asks the court to extend Lounsburry’s def-
inition of “significant range,” which pertains to a light work
analysis under Rule 202.00(c), to his case, which involves a
sedentary work analysis under Rule 201.07. He asserts that
applying Lounsburry, the ALJ erred at step five by identifying
only one occupation to which Tommasetti could adjust, i.e.,
semiconductor assembler. We do not agree. Lounsburry is
distinguishable because it involved a different grid rule that
was based on light exertion (Rule 202.07), whereas this case
involves a grid rule based on sedentary exertion (Rule
201.07). A plain reading of Rule 201.07 makes clear that it is
not augmented by Rule 202.00(c), the specific text which was
the driving consideration in 

.
Moreover, the grid rules related to sedentary exertion do not
contain the language of Rule 202.00(c).5 The Social Security
Administration has promulgated rules that treat jobs requiring
light exertion and sedentary exertion differently under the
grids. Tommasetti has not convinced us that we should do
otherwise. Accordingly, we reject Tommasetti’s attempt to
graft rules applicable to the light exertion grid onto the seden-
tary exertion grid. A contrary result would lead to the con-
fused and arbitrary application of grid rules from one
exertional category to other exertional categories and might
well, in effect, defeat the goal of consistency and uniformity
in decision-making that the particularized grids serve. See
Soc. Sec. Ruling 83-10 (1983) (stating that the regulations
were expanded to include Appendix 2 and the grids to “in-
crease consistency and promote the uniformity with which
disability determinations are made” at step five).
  5
   Tommasetti’s argument that Rule 201.00(e) is the “same provision” as
Rule 202.00(c) is not persuasive based on the text of the rules.
                    TOMMASETTI v. ASTRUE                 8845
                      IV.   Conclusion

   We affirm the district court’s conclusion that substantial
evidence supports the ALJ’s decision that Tommasetti was
not disabled and thus not entitled to disability benefits. The
ALJ provided clear and convincing reasons for rejecting Tom-
masetti’s testimony as not credible, and she provided specific
and legitimate reasons for discounting Dr. Nachenberg’s opin-
ions regarding Tommasetti’s physical limitations and ability
to perform sedentary work. Finally, although the ALJ erred at
step four in finding that Tommasetti could perform his past
work, this error was harmless because the ALJ properly con-
cluded as an alternative at step five that he could perform
work in the national and regional economies as a semiconduc-
tor assembler.

  AFFIRMED.