(Slip Opinion)              OCTOBER TERM, 2018                                       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., 200 U. S. 321, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

  BIESTEK v. BERRYHILL, ACTING COMMISSIONER
               OF SOCIAL SECURITY

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
                  THE SIXTH CIRCUIT

    No. 17–1184. Argued December 4, 2018—Decided April 1, 2019
Petitioner Michael Biestek, a former construction worker, applied for
  social security disability benefits, claiming he could no longer work
  due to physical and mental disabilities. The Social Security Admin-
  istration (SSA) assigned an Administrative Law Judge (ALJ) to con-
  duct a hearing, at which the ALJ had to determine whether Biestek
  could successfully transition to less physically demanding work. For
  guidance on that issue, the ALJ heard testimony from a vocational
  expert regarding the types of jobs Biestek could still perform and the
  number of such jobs that existed in the national economy. See 20
  CFR §§404.1560(c)(1), 416.960(c)(1). On cross-examination, Biestek’s
  attorney asked the expert “where [she was] getting [her numbers]
  from,” and the expert explained they were from her own individual
  labor market surveys. Biestek’s attorney then requested that the ex-
  pert turn over the surveys. The expert declined. The ALJ ultimately
  denied Biestek benefits, basing his conclusion on the expert’s testi-
  mony about the number of jobs available to him. Biestek sought re-
  view in federal court, where an ALJ’s factual findings are “conclu-
  sive” if supported by “substantial evidence,” 42 U. S. C. §405(g). The
  District Court rejected Biestek’s argument that the expert’s testimo-
  ny could not possibly constitute substantial evidence because she had
  declined to produce her supporting data. The Sixth Circuit affirmed.
Held: A vocational expert’s refusal to provide private market-survey
 data upon the applicant’s request does not categorically preclude the
 testimony from counting as “substantial evidence.”
    Substantial evidence is “more than a mere scintilla,” and means
  only “such relevant evidence as a reasonable mind might accept as
2                        BIESTEK v. BERRYHILL

                                  Syllabus

    adequate to support a conclusion.” Consolidated Edison Co. v.
    NLRB, 305 U. S. 197, 229. Biestek proposes a categorical rule that
    the testimony of a vocational expert who refuses a request for sup-
    porting data about job availability can never clear that bar. To as-
    sess that proposal, the Court begins with the parties’ common
    ground: Assuming no demand, a vocational expert’s testimony may
    count as substantial evidence even when unaccompanied by support-
    ing data.
      If that is true, is it not obvious why one additional fact—a refusal
    to a request for that data—should make an expert’s testimony cate-
    gorically inadequate. In some cases, the refusal to disclose data, con-
    sidered along with other shortcomings, will undercut an expert’s
    credibility and prevent a court from finding that “a reasonable mind”
    could accept the expert’s testimony. But in other cases, the refusal
    will have no such consequence. Similarly, the refusal will sometimes
    interfere with effective cross-examination, which a reviewing court
    may consider in deciding how much to credit an expert’s opinion. But
    other times, even without supporting data, an applicant will be able
    to probe the strength of the expert’s testimony on cross-examination.
    Ultimately, Biestek’s error lies in his pressing for a categorical rule,
    applying to every case in which a vocational expert refuses a request
    for underlying data. The inquiry, as is usually true in determining
    the substantiality of evidence, is case-by-case. It takes into account
    all features of the vocational expert’s testimony, as well as the rest of
    the administrative record, and defers to the presiding ALJ, who has
    seen the hearing up close. Pp. 5–11.
880 F. 3d 778, affirmed.

  KAGAN, J., delivered the opinion of the Court, in which ROBERTS,
C. J., and THOMAS, BREYER, ALITO, and KAVANAUGH, JJ., joined. SO-
TOMAYOR, J., filed a dissenting opinion. GORSUCH, J., filed a dissenting
opinion, in which GINSBURG, J., joined.
                       Cite as: 587 U. S. ____ (2019)                              1

                            Opinion of the Court

    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. 17–1184
                                  _________________


  MICHAEL J. BIESTEK, PETITIONER v. NANCY A.
    BERRYHILL, ACTING COMMISSIONER OF
               SOCIAL SECURITY
 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
            APPEALS FOR THE SIXTH CIRCUIT
                                [April 1, 2019]

  JUSTICE KAGAN delivered the opinion of the Court.
  The Social Security Administration (SSA) provides
benefits to individuals who cannot obtain work because of
a physical or mental disability. To determine whether an
applicant is entitled to benefits, the agency may hold an
informal hearing examining (among other things) the kind
and number of jobs available for someone with the appli-
cant’s disability and other characteristics. The agency’s
factual findings on that score are “conclusive” in judicial
review of the benefits decision so long as they are sup-
ported by “substantial evidence.” 42 U. S. C. §405(g).
  This case arises from the SSA’s reliance on an expert’s
testimony about the availability of certain jobs in the
economy. The expert largely based her opinion on private
market-survey data. The question presented is whether
her refusal to provide that data upon the applicant’s re-
quest categorically precludes her testimony from counting
as “substantial evidence.” We hold it does not.
2                  BIESTEK v. BERRYHILL

                      Opinion of the Court

                               I
  Petitioner Michael Biestek once worked as a carpenter
and general laborer on construction sites. But he stopped
working after he developed degenerative disc disease,
Hepatitis C, and depression. He then applied for social
security disability benefits, claiming eligibility as of Octo-
ber 2009.
  After some preliminary proceedings, the SSA assigned
an Administrative Law Judge (ALJ) to hold a hearing on
Biestek’s application. Those hearings, as described in the
Social Security Act, 49 Stat. 620, as amended, 42 U. S. C.
§301 et seq., are recognizably adjudicative in nature. The
ALJ may “receive evidence” and “examine witnesses”
about the contested issues in a case. §§405(b)(1), 1383(c)
(1)(A). But many of the rules governing such hear-
ings are less rigid than those a court would follow. See
Richardson v. Perales, 402 U. S. 389, 400–401 (1971). An
ALJ is to conduct a disability hearing in “an informal, non-
adversarial manner.”        20 CFR §404.900(b) (2018);
§416.1400(b). Most notably, an ALJ may receive evidence
in a disability hearing that “would not be admissible in
court.” §§404.950(c), 416.1450(c); see 42 U. S. C. §§405(b)
(1), 1383(c)(1)(A).
  To rule on Biestek’s application, the ALJ had to deter-
mine whether the former construction laborer could suc-
cessfully transition to less physically demanding work.
That required exploring two issues. The ALJ needed to
identify the types of jobs Biestek could perform notwith-
standing his disabilities. See 20 CFR §§404.1560(c)(1),
416.960(c)(1). And the ALJ needed to ascertain whether
those kinds of jobs “exist[ed] in significant numbers in the
national economy.” §§404.1560(c)(1), 416.960(c)(1); see
§§404.1566, 416.966.
  For guidance on such questions, ALJs often seek the
views of “vocational experts.”           See §§404.1566(e),
416.966(e); SSA, Hearings, Appeals, and Litigation Law
                  Cite as: 587 U. S. ____ (2019)            3

                      Opinion of the Court

Manual I–2–5–50 (Aug. 29, 2014). Those experts are
professionals under contract with SSA to provide impar-
tial testimony in agency proceedings. See id., at I–2–1–
31.B.1 (June 16, 2016); id., at I–2–5–48. They must have
“expertise” and “current knowledge” of “[w]orking condi-
tions and physical demands of various” jobs; “[k]nowledge
of the existence and numbers of [those jobs] in the national
economy”; and “[i]nvolvement in or knowledge of placing
adult workers[ ] with disabilities[] into jobs.” Id., at I–2–
1–31.B.1. Many vocational experts simultaneously work
in the private sector locating employment for persons with
disabilities. See C. Kubitschek & J. Dubin, Social Security
Disability Law & Procedure in Federal Court §3:89 (2019).
When offering testimony, the experts may invoke not only
publicly available sources but also “information obtained
directly from employers” and data otherwise developed
from their own “experience in job placement or career
counseling.” Social Security Ruling, SSR 00–4p, 65 Fed.
Reg. 75760 (2000).
   At Biestek’s hearing, the ALJ asked a vocational expert
named Erin O’Callaghan to identify a sampling of “seden-
tary” jobs that a person with Biestek’s disabilities, educa-
tion, and job history could perform. Tr. 59 (July 21, 2015);
see 20 CFR §§404.1567(a), 416.967(a) (defining a “seden-
tary” job as one that “involves sitting” and requires “lifting
no more than 10 pounds”). O’Callaghan had served as a
vocational expert in SSA proceedings for five years; she
also had more than ten years’ experience counseling peo-
ple with disabilities about employment opportunities. See
Stachowiak v. Commissioner of Social Security, 2013 WL
593825, *1 (ED Mich., Jan. 11, 2013); Record in No. 16–
10422 (ED Mich.), Doc. 17–13, p. 1274 (resume). In re-
sponse to the ALJ’s query, O’Callaghan listed sedentary
jobs “such as a bench assembler [or] sorter” that did not
require many skills. Tr. 58–59. And she further testified
that 240,000 bench assembler jobs and 120,000 sorter jobs
4                 BIESTEK v. BERRYHILL

                     Opinion of the Court

existed in the national economy. See ibid.
   On cross-examination, Biestek’s attorney asked
O’Callaghan “where [she was] getting those [numbers]
from.” Id., at 71. O’Callaghan replied that they came
from the Bureau of Labor Statistics and her “own individ-
ual labor market surveys.” Ibid. The lawyer then re-
quested that O’Callaghan turn over the private surveys so
he could review them. Ibid. O’Callaghan responded that
she wished to keep the surveys confidential because they
were “part of [her] client files.” Id., at 72. The lawyer
suggested that O’Callaghan could “take the clients’ names
out.” Ibid. But at that point the ALJ interjected that he
“would not require” O’Callaghan to produce the files in
any form. Ibid. Biestek’s counsel asked no further ques-
tions about the basis for O’Callaghan’s assembler and
sorter numbers.
   After the hearing concluded, the ALJ issued a decision
granting Biestek’s application in part and denying it in
part. According to the ALJ, Biestek was entitled to bene-
fits beginning in May 2013, when his advancing age (he
turned fifty that month) adversely affected his ability to
find employment. See App. to Pet. for Cert. 19a, 112a–
113a. But before that time, the ALJ held, Biestek’s dis-
abilities should not have prevented a “successful adjust-
ment to other work.” Id., at 110a–112a. The ALJ based
that conclusion on O’Callaghan’s testimony about the
availability in the economy of “sedentary unskilled occupa-
tions such as bench assembler [or] sorter.” Id., at 111a
(emphasis deleted).
   Biestek sought review in federal court of the ALJ’s
denial of benefits for the period between October 2009 and
May 2013. On judicial review, an ALJ’s factual findings—
such as the determination that Biestek could have found
sedentary work—“shall be conclusive” if supported by
“substantial evidence.” 42 U. S. C. §405(g); see supra,
at 1. Biestek contended that O’Callaghan’s testimony could
                  Cite as: 587 U. S. ____ (2019)              5

                      Opinion of the Court

not possibly constitute such evidence because she had
declined, upon request, to produce her supporting data.
See Plaintiff ’s Motion for Summary Judgment in No. 16–
10422 (ED Mich.), Doc. 22, p. 23. But the District Court
rejected that argument. See 2017 WL 1173775, *2 (Mar.
30, 2017). And the Court of Appeals for the Sixth Circuit
affirmed. See Biestek v. Commissioner of Social Security,
880 F. 3d 778 (2018). That court recognized that the
Seventh Circuit had adopted the categorical rule Biestek
proposed, precluding a vocational expert’s testimony from
qualifying as substantial if the expert had declined an
applicant’s request to provide supporting data. See id., at
790 (citing McKinnie v. Barnhart, 368 F. 3d 907, 910–911
(2004)). But that rule, the Sixth Circuit observed in join-
ing the ranks of unconvinced courts, “ha[d] not been a
popular export.” 880 F. 3d, at 790 (internal quotation
marks omitted).
  And no more is it so today.
                                II
   The phrase “substantial evidence” is a “term of art” used
throughout administrative law to describe how courts are
to review agency factfinding. T-Mobile South, LLC v.
Roswell, 574 U. S. ___, ___ (2015) (slip op., at 7). Under
the substantial-evidence standard, a court looks to an
existing administrative record and asks whether it con-
tains “sufficien[t] evidence” to support the agency’s factual
determinations. Consolidated Edison Co. v. NLRB, 305
U. S. 197, 229 (1938) (emphasis deleted). And whatever
the meaning of “substantial” in other contexts, the thresh-
old for such evidentiary sufficiency is not high. Substan-
tial evidence, this Court has said, is “more than a mere
scintilla.” Ibid.; see, e.g., Perales, 402 U. S., at 401 (inter-
nal quotation marks omitted). It means—and means
only—“such relevant evidence as a reasonable mind might
accept as adequate to support a conclusion.” Consolidated
6                      BIESTEK v. BERRYHILL

                          Opinion of the Court

Edison, 305 U. S., at 229. See Dickinson v. Zurko, 527
U. S. 150, 153 (1999) (comparing the substantial-evidence
standard to the deferential clearly-erroneous standard).
   Today, Biestek argues that the testimony of a vocational
expert who (like O’Callaghan) refuses a request for sup-
porting data about job availability can never clear the
substantial-evidence bar. See Brief for Petitioner 21–34.
As that formulation makes clear, Biestek’s proposed rule
is categorical, rendering expert testimony insufficient to
sustain an ALJ’s factfinding whenever such a refusal has
occurred.1 But Biestek hastens to add two caveats. The
first is to clarify what the rule is not, the second to stress
where its limits lie.
   Biestek initially takes pains—and understandably so—
to distinguish his argument from a procedural claim.
Reply Brief 12–14. At no stage in this litigation, Biestek
says, has he ever espoused “a free-standing procedural
rule under which a vocational expert would always have to
produce [her underlying data] upon request.” Id., at 2.
That kind of rule exists in federal court: There, an expert
witness must produce all data she has considered in reach-
ing her conclusions. See Fed. Rule Civ. Proc. 26(a)(2)(B).
But as Biestek appreciates, no similar requirement applies
——————
  1 In contrast, the principal dissent cannot decide whether it favors

such a categorical rule. At first, JUSTICE GORSUCH endorses the rule
Biestek and the Seventh Circuit have proposed. See post, at 2. But in
then addressing our opinion, he takes little or no issue with the reason-
ing we offer to show why that rule is too broad. See post, at 4–7. So the
dissent tries to narrow the scope of Biestek’s categorical rule—to only
cases that look just like his. See post, at 7–8. And still more, it shelves
all the “categorical” talk and concentrates on Biestek’s case alone. See
post, at 1, 4–8. There, JUSTICE GORSUCH’s dissent joins JUSTICE
SOTOMAYOR’s in concluding that the expert evidence in this case was
insubstantial. But as we later explain, see infra, at 11, Biestek did not
petition us to resolve that factbound question; nor did his briefing and
argument focus on anything other than the Seventh Circuit’s categori-
cal rule. We confine our opinion accordingly.
                  Cite as: 587 U. S. ____ (2019)            7

                      Opinion of the Court

in SSA hearings. As explained above, Congress intended
those proceedings to be “informal” and provided that the
“strict rules of evidence, applicable in the courtroom, are
not to” apply. Perales, 402 U. S., at 400; see 42 U. S. C.
§405(b)(1); supra, at 2. So Biestek does not press for a
“procedural rule” governing “the means through which an
evidentiary record [must be] created.” Tr. of Oral Arg. 6;
Reply Brief 13. Instead, he urges a “substantive rule” for
“assess[ing] the quality and quantity of [record] evi-
dence”—which would find testimony like O’Callaghan’s
inadequate, when taken alone, to support an ALJ’s fact-
finding. Id., at 12.
   And Biestek also emphasizes a limitation within that
proposed rule. For the rule to kick in, the applicant must
make a demand for the expert’s supporting data. See
Brief for Petitioner i, 5, 18, 40, 55; Tr. of Oral Arg. 25–26.
Consider two cases in which vocational experts rely on,
but do not produce, nonpublic information. In the first,
the applicant asks for the data; in the second, not. Accord-
ing to Biestek, the expert’s testimony in the first case
cannot possibly clear the substantial-evidence bar; but in
the second case, it may well do so, even though the admin-
istrative record is otherwise the same. And Biestek un-
derscores that this difference in outcome has nothing to do
with waiver or forfeiture: As he acknowledges, an appli-
cant “cannot waive the substantial evidence standard.”
Id., at 27. It is just that the evidentiary problem arises
from the expert’s refusal of a demand, not from the data’s
absence alone. In his words, the testimony “can constitute
substantial evidence if unchallenged, but not if chal-
lenged.” Reply Brief 18.
   To assess Biestek’s proposal, we begin with the parties’
common ground: Assuming no demand, a vocational ex-
pert’s testimony may count as substantial evidence even
when unaccompanied by supporting data. Take an exam-
ple. Suppose an expert has top-of-the-line credentials,
8                      BIESTEK v. BERRYHILL

                          Opinion of the Court

including professional qualifications and many years’
experience; suppose, too, she has a history of giving sound
testimony about job availability in similar cases (perhaps
before the same ALJ). Now say that she testifies about
the approximate number of various sedentary jobs an
applicant for benefits could perform. She explains that
she arrived at her figures by surveying a range of repre-
sentative employers; amassing specific information about
their labor needs and employment of people with disabili-
ties; and extrapolating those findings to the national
economy by means of a well-accepted methodology. She
answers cogently and thoroughly all questions put to her
by the ALJ and the applicant’s lawyer. And nothing in the
rest of the record conflicts with anything she says. But
she never produces her survey data. Still, her testimony
would be the kind of evidence—far “more than a mere
scintilla”—that “a reasonable mind might accept as ade-
quate to support” a finding about job availability. Consol-
idated Edison, 305 U. S., at 229. Of course, the testimony
would be even better—more reliable and probative—if she
had produced supporting data; that would be a best prac-
tice for the SSA and its experts.2 And of course, a different
(maybe less qualified) expert failing to produce such data
might offer testimony that is so feeble, or contradicted,
that it would fail to clear the substantial-evidence bar.
The point is only—as, again, Biestek accepts—that expert
testimony can sometimes surmount that bar absent under-
lying data.
   But if that is true, why should one additional fact—a
——————
   2 The SSA itself appears to agree.     In the handbook given to voca-
tional experts, the agency states: “You should have available, at
the hearing, any vocational resource materials that you are likely
to rely upon” because “the ALJ may ask you to provide relevant
portions of [those] materials.” SSA, Vocational Expert Handbook 37
(Aug. 2017), https://www.ssa.gov/appeals/public_experts/Vocational_Experts_
(VE)_Handbook-508.pdf (as last visited Mar. 28, 2019).
                 Cite as: 587 U. S. ____ (2019)            9

                     Opinion of the Court

refusal to a request for that data—make a vocational
expert’s testimony categorically inadequate? Assume that
an applicant challenges our hypothetical expert to turn
over her supporting data; and assume the expert declines
because the data reveals private information about her
clients and making careful redactions will take a fair bit of
time. Nothing in the expert’s refusal changes her testi-
mony (as described above) about job availability. Nor does
it alter any other material in the record. So if our expert’s
opinion was sufficient—i.e., qualified as substantial evi-
dence—before the refusal, it is hard to see why the opinion
has to be insufficient afterward.
   Biestek suggests two reasons for that non-obvious re-
sult. First, he contends that the expert’s rejection of a
request for backup data necessarily “cast[s her testimony]
into doubt.” Reply Brief 16. And second, he avers that the
refusal inevitably “deprives an applicant of the material
necessary for an effective cross-examination.” Id., at 2.
But Biestek states his arguments too broadly—and the
nuggets of truth they contain cannot justify his proposed
flat rule.
   Consider Biestek’s claim about how an expert’s refusal
undercuts her credibility. Biestek here invokes the estab-
lished idea of an “adverse inference”: If an expert declines
to back up her testimony with information in her control,
then the factfinder has a reason to think she is hiding
something. See id., at 16 (citing cases). We do not dispute
that possibility—but the inference is far from always
required. If an ALJ has no other reason to trust the ex-
pert, or finds her testimony iffy on its face, her refusal of
the applicant’s demand for supporting data may properly
tip the scales against her opinion. (Indeed, more can be
said: Even if the applicant makes no demand, such an
expert’s withholding of data may count against her.) But
if (as in our prior hypothetical example, see supra, at 7–8)
the ALJ views the expert and her testimony as otherwise
10                 BIESTEK v. BERRYHILL

                     Opinion of the Court

trustworthy, and thinks she has good reason to keep her
data private, her rejection of an applicant’s demand need
not make a difference. So too when a court reviews the
ALJ’s decision under the deferential substantial-evidence
standard. In some cases, the refusal to disclose data,
considered along with other shortcomings, will prevent a
court from finding that “a reasonable mind” could accept
the expert’s testimony. Consolidated Edison, 305 U. S., at
229. But in other cases, that refusal will have no such
consequence. Even taking it into account, the expert’s
opinion will qualify as “more than a mere scintilla” of
evidence supporting the ALJ’s conclusion. Which is to say
it will count, contra Biestek, as substantial.
   And much the same is true of Biestek’s claim that an
expert’s refusal precludes meaningful cross-examination.
We agree with Biestek that an ALJ and reviewing court
may properly consider obstacles to such questioning when
deciding how much to credit an expert’s opinion. See
Perales, 402 U. S., at 402–406. But Biestek goes too far in
suggesting that the refusal to provide supporting data
always interferes with effective cross-examination, or that
the absence of such testing always requires treating an
opinion as unreliable. Even without specific data, an
applicant may probe the strength of testimony by asking
an expert about (for example) her sources and methods—
where she got the information at issue and how she ana-
lyzed it and derived her conclusions. See, e.g., Chavez v.
Berryhill, 895 F. 3d 962, 969–970 (CA7 2018). And even
without significant testing, a factfinder may conclude that
testimony has sufficient indicia of reliability to support a
conclusion about whether an applicant could find work.
Indeed, Biestek effectively concedes both those points in
cases where supporting data is missing, so long as an
expert has not refused an applicant’s demand. See supra,
at 7. But once that much is acknowledged, Biestek’s
argument cannot hold. For with or without an express
                  Cite as: 587 U. S. ____ (2019)           11

                      Opinion of the Court

refusal, the absence of data places the selfsame limits on
cross-examination.
   Where Biestek goes wrong, at bottom, is in pressing for
a categorical rule, applying to every case in which a voca-
tional expert refuses a request for underlying data. Some-
times an expert’s withholding of such data, when com-
bined with other aspects of the record, will prevent her
testimony from qualifying as substantial evidence. That
would be so, for example, if the expert has no good reason
to keep the data private and her testimony lacks other
markers of reliability. But sometimes the reservation of
data will have no such effect. Even though the applicant
might wish for the data, the expert’s testimony still will
clear (even handily so) the more-than-a-mere-scintilla
threshold. The inquiry, as is usually true in determining
the substantiality of evidence, is case-by-case. See, e.g.,
Perales, 402 U. S., at 399, 410 (rejecting a categorical rule
pertaining to the substantiality of medical reports in a
disability hearing). It takes into account all features of
the vocational expert’s testimony, as well as the rest of the
administrative record. And in so doing, it defers to the
presiding ALJ, who has seen the hearing up close.
   That much is sufficient to decide this case. Biestek
petitioned us only to adopt the categorical rule we have
now rejected. He did not ask us to decide whether, in the
absence of that rule, substantial evidence supported the
ALJ in denying him benefits. Accordingly, we affirm the
Court of Appeals’ judgment.
                                             It is so ordered.
                 Cite as: 587 U. S. ____ (2019)           1

                   SOTOMAYOR, J., dissenting

SUPREME COURT OF THE UNITED STATES
                         _________________

                         No. 17–1184
                         _________________


  MICHAEL J. BIESTEK, PETITIONER v. NANCY A.
    BERRYHILL, ACTING COMMISSIONER OF
               SOCIAL SECURITY
 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
            APPEALS FOR THE SIXTH CIRCUIT
                        [April 1, 2019]

  JUSTICE SOTOMAYOR, dissenting.
  The Court focuses on the propriety of a categorical rule
that precludes private data that a vocational expert refuses
to provide upon request from qualifying as “ ‘substantial
evidence.’ ” See ante, at 1. I agree with JUSTICE GORSUCH
that the question presented by this case encompasses an
inquiry not just into the propriety of a categorical rule in
such circumstances but also into whether the substantial-
evidence standard was met in the narrower circumstances
of Michael Biestek’s case. See post, at 6–7 (dissenting
opinion). For the reasons that JUSTICE GORSUCH sets out,
the vocational expert’s conclusory testimony in this case,
offered without even a hint of support, did not constitute
substantial evidence.
  Once Biestek established that he had impairments, the
agency bore the burden of proving that work opportunities
were available to someone with his disabilities and indi-
vidual characteristics. 20 CFR § 416.912(b)(3) (2018). To
meet that burden, the agency relied on a vocational ex-
pert’s testimony that Biestek could qualify for one of
240,000 “bench assembler” jobs or 120,000 “sorter” jobs
nationwide. Tr. 59 (July 21, 2015). The expert said that
those numbers were based in part on her “professional
experience.” Id., at 61. When Biestek’s counsel under-
2                  BIESTEK v. BERRYHILL

                   SOTOMAYOR, J., dissenting

standably asked for more details, the expert said only that
she got the numbers from a publicly available source as
well as from her “own individual labor market surveys”
that were part of confidential client files. Id., at 71; see
id., at 67, 71–72. Biestek’s counsel asked if the names in
the files could be redacted, but the administrative law
judge (ALJ) interrupted and ruled that she would not
require the surveys to be produced in redacted form. Id.,
at 72; see also id., at 67.
   Perhaps the ALJ would have allowed Biestek’s counsel
to ask followup questions about the basis for the testimony
at that point, and perhaps Biestek’s counsel should have
tried to do so. But a Social Security proceeding is “inquisi-
torial rather than adversarial.” Sims v. Apfel, 530 U. S.
103, 110–111 (2000); see 20 CFR §§404.900(b),
416.1400(b). The ALJ acts as “an examiner charged with
developing the facts,” Richardson v. Perales, 402 U. S. 389,
410 (1971), and has a duty to “develop the arguments both
for and against granting benefits,” Sims, 530 U. S., at 111;
see also Social Security Ruling, SSR 00–4P, 65 Fed. Reg.
75760 (2000) (noting “the adjudicator’s duty to fully de-
velop the record”). Here, instead of taking steps to ensure
that the claimant had a basis from which effective cross-
examination could be made and thus the record could be
developed, the ALJ cut off that process by intervening
when Biestek’s counsel asked about the possibility of
redaction.
   The result was that the expert offered no detail whatso-
ever on the basis for her testimony. She did not say whom
she had surveyed, how many surveys she had conducted,
or what information she had gathered, nor did she offer
any other explanation of the data on which she relied. In
conjunction with the failure to proffer the surveys them-
selves, the expert’s conclusory testimony alone could not
constitute substantial evidence to support the ALJ’s fact-
                     Cite as: 587 U. S. ____ (2019)                    3

                       SOTOMAYOR, J., dissenting

finding.*
   I agree with much of JUSTICE GORSUCH’s reasoning. I
emphasize that I do not foreclose the possibility that a
more developed record could justify an ALJ’s reliance on
vocational-expert testimony in some circumstances even if
the expert does not produce records underlying that testi-
mony on request. An expert may have legitimate reasons
for not turning over data, such as the burden of gathering
records or confidentiality concerns that redaction cannot
address. In those circumstances, as the majority suggests,
the agency may be able to support an expert’s testimony in
ways other than by providing underlying data, such as by
offering a fulsome description of the data and methodology
on which the expert relies. See ante, at 8. The agency
simply did not do so here.




——————
  * I note that the agency’s own handbook says that experts “should
have available, at the hearing, any vocational resource materials that
[they] are likely to rely upon and should be able to thoroughly explain
what resource materials [they] used and how [they] arrived at [their]
opinions.”    SSA, Vocational Expert Handbook 37 (Aug. 2017),
https://www.ssa.gov / appeals / public_experts / Vocational_Experts_(VE)_
Handbook-508.pdf (as last visited Mar. 29, 2019).
                 Cite as: 587 U. S. ____ (2019)            1

                    GORSUCH, J., dissenting

SUPREME COURT OF THE UNITED STATES
                         _________________

                         No. 17–1184
                         _________________


  MICHAEL J. BIESTEK, PETITIONER v. NANCY A.
    BERRYHILL, ACTING COMMISSIONER OF
               SOCIAL SECURITY
 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
            APPEALS FOR THE SIXTH CIRCUIT
                        [April 1, 2019]

  JUSTICE GORSUCH, with whom JUSTICE GINSBURG joins,
dissenting.
  Walk for a moment in Michael Biestek’s shoes. As part
of your application for disability benefits, you’ve proven
that you suffer from serious health problems and can’t
return to your old construction job. Like many cases,
yours turns on whether a significant number of other jobs
remain that someone of your age, education, and experi-
ence, and with your physical limitations, could perform.
When it comes to that question, the Social Security Ad-
ministration bears the burden of proof. To meet its bur-
den in your case, the agency chooses to rest on the testi-
mony of a vocational expert the agency hired as an
independent contractor. The expert asserts there are
120,000 “sorter” and 240,000 “bench assembler” jobs
nationwide that you could perform even with your
disabilities.
  Where did these numbers come from? The expert says
she relied on data from the Bureau of Labor Statistics and
her own private surveys. But it turns out the Bureau
can’t be the source; its numbers aren’t that specific. The
source—if there is a source—must be the expert’s private
surveys. So you ask to see them. The expert refuses—she
says they’re part of confidential client files. You reply by
2                  BIESTEK v. BERRYHILL

                    GORSUCH, J., dissenting

pointing out that any confidential client information can
be redacted. But rather than ordering the data produced,
the hearing examiner, herself a Social Security Admin-
istration employee, jumps in to say that won’t be neces-
sary. Even without the data, the examiner states in her
decision on your disability claim, the expert’s say-so war-
rants “great weight” and is more than enough evidence to
deny your application. Case closed. App. to Pet. for Cert.
111a–112a, 118a–119a.
   Would you say this decision was based on “substantial
evidence”? Count me with Judge Easterbrook and the
Seventh Circuit in thinking that an agency expert’s bottom-
line conclusion, supported only by a claim of readily avail-
able evidence that she refuses to produce on request, fails
to satisfy the government’s statutory burden of producing
substantial evidence of available other work. See Don-
ahue v. Barnhart, 279 F. 3d 441, 446 (CA7 2002);
McKinnie v. Barnhart, 368 F. 3d 907, 910–911 (CA7 2004)
(per curiam).
   Start with the legal standard. The Social Security Act
of 1935 requires the agency to support its conclusions
about the number of available jobs with “substantial
evidence.” 42 U. S. C. §405(g). Congress borrowed that
standard from civil litigation practice, where reviewing
courts may overturn a jury verdict when the record lacks
“substantial evidence”—that is, evidence sufficient to
permit a reasonable jury to reach the verdict it did. Much
the same standard governs summary judgment and di-
rected verdict practice today. See 2 K. Hickman & R.
Pierce, Administrative Law §10.2.1, pp. 1082–1085 (6th
ed. 2019); Anderson v. Liberty Lobby, Inc., 477 U. S. 242,
252 (1986); NLRB v. Columbian Enameling & Stamping
Co., 306 U. S. 292, 300 (1939).
   Next, consider what we know about this standard.
Witness testimony that’s clearly wrong as a matter of fact
cannot be substantial evidence. See Scott v. Harris, 550
                  Cite as: 587 U. S. ____ (2019)            3

                     GORSUCH, J., dissenting

U. S. 372, 380 (2007). Falsified evidence isn’t substantial
evidence. See, e.g., Firemen’s and Policemen’s Civil Serv.
Comm’n v. Brinkmeyer, 662 S. W. 2d 953, 956 (Tex. 1984).
Speculation isn’t substantial evidence. See, e.g., Cao He
Lin v. Department of Justice, 428 F. 3d 391, 400 (CA2
2005); Alpo Petfoods, Inc. v. NLRB, 126 F. 3d 246, 250
(CA4 1997). And, maybe most pointedly for our purposes,
courts have held that a party or expert who supplies only
conclusory assertions fails this standard too. See, e.g.,
Lujan v. National Wildlife Federation, 497 U. S. 871, 888
(1990) (“The object of [summary-judgment practice] is not
to replace conclusory allegations of the complaint or an-
swer with conclusory allegations of an affidavit”); Regents
of Univ. of Minn. v. AGA Medical Corp., 717 F. 3d 929, 941
(CA Fed. 2013) (“conclusory expert assertions cannot raise
triable issues of material fact”) (collecting cases); Mid-
State Fertilizer Co. v. Exchange Nat. Bank of Chicago, 877
F. 2d 1333, 1339 (CA7 1989) (“An expert who supplies
nothing but a bottom line supplies nothing of value to the
judicial process”); Sea Robin Pipeline Co. v. FERC, 795
F. 2d 182, 188 (CADC 1986) (“[I]nordinate faith in the
conclusory assertions of an expert . . . cannot satisfy the
requirement [of] substantial evidence”).
   If clearly mistaken evidence, fake evidence, speculative
evidence, and conclusory evidence aren’t substantial evi-
dence, the evidence here shouldn’t be either. The case
hinges on an expert who (a) claims to possess evidence on
the dispositive legal question that can be found nowhere
else in the record, but (b) offers only a conclusion about its
contents, and (c) refuses to supply the evidence when
requested without showing that it can’t readily be made
available. What reasonable factfinder would rely on evi-
dence like that? It seems just the sort of conclusory evi-
dence courts have long held insufficient to meet the sub-
stantial evidence standard. And thanks to its conclusory
nature, for all anyone can tell it may have come out of a
4                  BIESTEK v. BERRYHILL

                    GORSUCH, J., dissenting

hat—and, thus, may wind up being clearly mistaken, fake,
or speculative evidence too. Unsurprisingly given all this,
the government fails to cite even a single authority bless-
ing the sort of evidence here as substantial evidence,
despite the standard’s long history and widespread use.
  Veteran Social Security practitioners must be feeling a
sense of déjà vu. Half a century ago, Judge Henry Friendly
encountered Kerner v. Flemming, 283 F. 2d 916 (CA2
1960). There, the agency’s hearing examiner offered
“nothing save [his own] speculation” to support his holding
that the claimant “could in fact obtain substantial gainful
employment.” Id., at 921. The Second Circuit firmly
explained that this kind of conclusory claim is insufficient
to meet the substantial evidence standard. In response,
the Social Security Administration began hiring vocational
experts, like the one in this case, to document the number
of jobs available to a given claimant. But if the govern-
ment can do what it did in this case, it’s hard to see what
all the trouble was for. The agency might still rest deci-
sions on a hunch—just so long as the hunch comes from an
agency contractor rather than an agency examiner.
  Instead of addressing the realities of this case, the
government asks us to imagine a hypothetical one. As-
sume, it says, that no one had requested the underlying
data. In those circumstances, the government points out,
even Mr. Biestek appears to accept that the agency’s
decision could have stood. And if that’s true, the govern-
ment asks, why should it make a difference if we add only
one additional fact—the expert’s refusal to produce the
data? See ante, at 7–9 (presenting the same argument).
  The answer is an old and familiar one. The refusal to
supply readily available evidentiary support for a conclu-
sion strongly suggests that the conclusion is, well, unsup-
ported. See, e.g., Interstate Circuit, Inc. v. United States,
306 U. S. 208, 226 (1939) (“The production of weak evi-
dence when strong is available can lead only to the conclu-
                 Cite as: 587 U. S. ____ (2019)            5

                    GORSUCH, J., dissenting

sion that the strong would have been adverse”); Clifton v.
United States, 4 How. 242, 248 (1846) (the withholding of
“more direct” proof suggests that “if the more perfect
exposition had been given it would have laid open defi-
ciencies and objections which the more obscure and uncer-
tain testimony was intended to conceal”); 31A C. J. S.,
Evidence §156(2), p. 402 (1964) (“The unfavorable infer-
ence . . . is especially applicable where the party withhold-
ing the evidence has had notice or has been ordered to
produce it”). Meanwhile, a similar inference may not arise
if no one’s bothered to ask for the evidence, or if the evi-
dence is shown to be unavailable for a good reason. In
cases like those, there may be just too many other plaus-
ible and innocent excuses for the evidence’s absence. Maybe,
for example, nobody bothered to seek the underlying data
because everyone knew what it would show.
   Fine, the Court responds, all that’s true enough. But
even if we accept that an expert’s failure to produce the
evidence underlying her conclusion may support an infer-
ence that her conclusion is unsupported, that doesn’t
mean such an inference must follow. Whether an infer-
ence is appropriate depends on the facts of the particular
case. See ante, at 9–10.
   But what more do we need to know about the facts of
this case? All of the relevant facts are undisputed, and it
remains only to decide the legal question whether they
meet the substantial evidence standard. We know that
the expert offered a firm and exact conclusion about the
number of available jobs. We know that the expert
claimed to have private information to support her conclu-
sion. We know Mr. Biestek requested that information
and we have no reason to think any confidentiality con-
cerns could not have been addressed. We know, too, that
the hearing examiner had “no other reason to trust the
expert[’s]” numbers beyond her say-so. Ibid. Finally and
looking to the law, we know that a witness’s bare conclu-
6                  BIESTEK v. BERRYHILL

                    GORSUCH, J., dissenting

sion is regularly held insufficient to meet the substantial
evidence threshold—and we know that the government
hasn’t cited a single case finding substantial evidence on
so little. This is exactly the sort of case where an adverse
inference should “tip the scales.” Ibid.
   With so much now weighing against the government,
everything seems to turn on a final hypothetical. Now we
are asked to imagine that the expert had offered detailed
oral testimony about the withheld data. Her testimony
was so detailed, we are asked to suppose, that Mr. Biestek
could have thoroughly tested the data’s reliability through
cross-examination. (You might wonder just how effective
this cross-examination could be if Mr. Biestek didn’t have
access to the data. But overlook that.) Surely in those
circumstances it wouldn’t matter whether the expert
failed to produce the data even in bad faith. Any failure to
produce would be harmless as a matter of law because the
expert’s testimony, all by itself, would amount to substan-
tial evidence on which a rational factfinder might rely.
Ante, at 10.
   The problem is that this imaginary case has nothing to
teach us about our real one. In Mr. Biestek’s case, it is
undisputed that the expert offered only a bare conclusion
about the number of available jobs. No other relevant
testimony was offered or received: no testimony about the
underlying data, no testimony about its specific sources,
no testimony about its reliability. In our real case, there is
simply no way to shrug off the failure to produce the data
as harmless error. To the contrary, and as we have seen,
cases like this routinely fail to satisfy the substantial
evidence standard. And if the government has a “duty to
fully develop the record,” ante, at 2 (SOTOMAYOR, J., dis-
senting), that conclusion should follow all the more
strongly.
   What leads the Court to a different conclusion? It says
that it views Mr. Biestek’s petition as raising only the
                 Cite as: 587 U. S. ____ (2019)            7

                    GORSUCH, J., dissenting

“categorical” question whether an expert’s failure to pro-
duce underlying data always and in “every case” precludes
her testimony from qualifying as substantial evidence.
Ante, at 1, 9–11. And once the question is ratcheted up to
that level of abstraction, of course it is easy enough to
shoot it down: just point to a series of hypothetical cases
where the record contains additional justification for the
expert’s failure to produce or additional evidence to sup-
port her opinion. In such counterfactual cases, the failure
to produce either would not be enough to give rise to an
adverse inference under traditional legal principles or
could be held harmless as a matter of law. See ante,
at 7–10.
  But as I understand Mr. Biestek’s submission, it does
not require an all-or-nothing approach that would cover
“every case.” As the Court acknowledges, Mr. Biestek has
focused us “on the Seventh Circuit’s categorical rule.”
Ante, at 6, n. 1. And that “rule” targets the narrower
“category” of circumstances we have here—where an
expert “ ‘give[s] a bottom line,’ ” fails to provide evidence
“underlying that bottom line” when challenged, and fails
to show the evidence is unavailable. McKinnie, 368 F. 3d,
at 911 (quoting Donahue, 279 F. 3d, at 446). What to do
about that category falls well within the question presented:
“[w]hether a vocational expert’s testimony can consti-
tute substantial evidence of ‘other work’ . . . when the
expert fails upon the applicant’s request to provide the
underlying data on which that testimony is premised.”
Pet. for Cert. i. The answer to that question may be “al-
ways,” “never,” or—as the Court itself seems to
acknowledge—“[s]ometimes.” Ante, at 11. And if the
answer is “sometimes,” the critical question becomes “in
what circumstances”?
  I suppose we could stop short and leave everyone guess-
ing. But another option is to follow the Seventh Circuit’s
lead, resolve the smaller yet still significant “category” of
8                  BIESTEK v. BERRYHILL

                    GORSUCH, J., dissenting

cases like the one before us, and in that way begin to offer
lower courts meaningful guidance in this important area.
While I would not hesitate to take this course and make
plain that cases like Mr. Biestek’s fail the substantial
evidence standard, I understand the Court today to choose
the first option and leave these matters for another day.
   There is good news and bad news in this. If my under-
standing of the Court’s opinion is correct, the good news is
that the Court remains open to the possibility that in real-
world cases like Mr. Biestek’s, lower courts may—and
even should—find the substantial evidence test unmet.
The bad news is that we must wait to find out, leaving
many people and courts in limbo in the meantime. Cases
with facts like Mr. Biestek’s appear to be all too common.
See, e.g., Dubin, Overcoming Gridlock: Campbell After a
Quarter-Century and Bureaucratically Rational Gap-
Filling in Mass Justice Adjudication in the Social Security
Administration’s Disability Programs, 62 Admin. L. Rev.
937, 966 (2010). And many courts have erred in them by
finding the substantial evidence test met, as the Sixth
Circuit did in the case now before us. Some courts have
even conflated the substantial evidence standard—a sub-
stantive standard governing what’s needed to sustain a
judgment as a matter of law—with procedural rules gov-
erning the admission of evidence. These courts have
mistakenly suggested that, because the Federal Rules of
Evidence don’t apply in Social Security proceedings, any-
thing an expert says will suffice to meet the agency’s
burden of proof. See, e.g., Welsh v. Commissioner of Social
Security, 662 Fed. Appx. 105, 109–110 (CA3 2016); Bayliss
v. Barnhart, 427 F. 3d 1211, 1218, and n. 4 (CA9 2005).
Definitively resolving this case would have provided more
useful guidance for practitioners and lower courts that
have struggled with a significant category of cases like Mr.
Biestek’s, all while affording him the relief the law prom-
ises in disputes like his.
                 Cite as: 587 U. S. ____ (2019)           9

                    GORSUCH, J., dissenting

   The principle that the government must support its
allegations with substantial evidence, not conclusions and
secret evidence, guards against arbitrary executive deci-
sionmaking. See Friendly, “Some Kind of Hearing,” 123
U. Pa. L. Rev. 1267, 1313–1314 (1975). Without it, people
like Mr. Biestek are left to the mercy of a bureaucrat’s
caprice. Over 100 years ago, in ICC v. Louisville & Nash-
ville R. Co., 227 U. S. 88 (1913), the government sought to
justify an agency order binding private parties without
producing the information on which the agency had relied.
The government argued that its findings should be “pre-
sumed to have been supported.” Id., at 93. In essence, the
government sought the right to “act upon any sort of se-
cret evidence.” Gellhorn, Official Notice in Administrative
Adjudication, 20 Texas L. Rev. 131, 145 (1941). This
Court did not approve of that practice then, and I would
not have hesitated to make clear that we do not approve of
it today.
   I respectfully dissent.
