97-1709
In the Supreme Court of the United States
OCTOBER TERM, 1997
KUMHO TIRE COMPANY, LTD., ET AL., PETITIONERS
v.
PATRICK CARMICHAEL, ET AL.
ON WRIT OF CERTIORARI TO
THE UNITED STATES COURT OF APPEALS
FOR THE ELEVENTH CIRCUIT
BRIEF FOR THE UNITED STATES
AS AMICUS CURIAE SUPPORTING PETITIONERS
SETH P. WAXMAN
Solicitor General
Counsel of Record
FRANK W. HUNGER
Assistant Attorney General
LAWRENCE G. WALLACE
Deputy Solicitor General
JEFFREY P. MINEAR
Assistant to the Solicitor
General
ANTHONY J. STEINMEYER
JOHN P. SCHNITKER
Attorneys
Department of Justice
Washington, D.C. 20530-0001
(202) 514-2217
QUESTION PRESENTED
Whether this Court's decision in Daubert v. Merrell Dow Pharmaceuticals,
Inc., 509 U.S. 579 (1993), which clarifies the standards for admission of
expert testimony under Rule 702 of the Federal Rules of Evidence, applies
to the admission of testimony from an expert witness who bases his opinion
on "skill- or experience-based observation."
In the Supreme Court of the United States
OCTOBER TERM, 1997
No. 97-1709
KUMHO TIRE COMPANY, LTD., ET AL., PETITIONERS
v.
PATRICK CARMICHAEL, ET AL.
ON WRIT OF CERTIORARI TO
THE UNITED STATES COURT OF APPEALS
FOR THE ELEVENTH CIRCUIT
BRIEF FOR THE UNITED STATES
AS AMICUS CURIAE SUPPORTING PETITIONERS
INTEREST OF THE UNITED STATES
The United States has a distinctive interest in the interpretation of the
Federal Rules of Evidence by virtue of the government's exclusive responsibility
for enforcing federal criminal laws and its involvement in a far greater
number of civil cases nationwide than "even the most litigious private
entity." United States v. Mendoza, 464 U.S. 154, 159 (1984). The United
States therefore has participated in previous cases bearing on the admission
of expert testimony under Rule 702 of those Rules. See Daubert v. Merrell
Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993); General Electric Co. v.
Joiner, 118 S. Ct. 512 (1997). Because the United States litigates in diverse
capacities, it has a broad perspective on the development of nationally
applicable standards governing admission of expert testimony.
STATEMENT
Petitioners manufacture and distribute automobile tires. Respondents brought
a diversity action against petitioners in the United States District Court
for the Southern District of Alabama claiming that petitioners are liable
under state product liability and tort law for injuries that respondents
suffered as a consequence of an automobile accident. The district court
excluded the testimony of respondents' expert that the tire on the automobile
was defective and granted summary judgment for petitioners. Pet. App. 1b-20b;
see also id. at 1c-6c. The court of appeals reversed, ruling that the district
court had erred as a matter of law in applying this Court's decision in
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), to expert
testimony that rests on "skill- or experienced-based observation."
Pet. App. 1a-10a.
1. Respondent Patrick J. Carmichael purchased a Ford Aerostar XL minivan
from a car dealership in the State of Washington. At the time of purchase,
the van's odometer registered 88,997 miles. Two months and 7,011 miles later,
the right rear tire failed while Carmichael was driving the vehicle in Alabama.
Respondents, Carmichael and seven members of his family, suffered severe
injuries in the resulting accident. Petitioner Kumho Tire Company, Ltd.,
had designed and manufactured the tire at issue for petitioner Hercules
Tire and Rubber Company, Inc. Pet. App. 2b-4b; Pet. 3 & n.1.
2. Respondents' complaint alleges that the tire that Kumho Tire Company
had designed and manufactured was defective and that petitioners are therefore
liable under the Alabama Extended Manufacturers Liability Doctrine, see
Casrell v. Altec Industries, Inc., 335 So.2d 128 (Ala. 1976), as well as
under state common law principles of negligence, wantonness, and breach
of warranty. To prove that the tire was defective, respondents sought out
expert testimony. See Fed. R. Evid. 702. Respondents initially intended
to call George R. Edwards, of George R. Edwards and Associates, as a tire
consultant, but Edwards became ill and respondents ultimately relied on
an employee of that firm, Dennis Carlson. Pet. App. 7b, 9b n.6. Among his
credentials, Carlson had earned a master's degree in mechanical engineering,
worked 10 years for Michelin America in the field of tire design, and later
worked as a consultant in cases involving tire failure. Id. at 7b-8b.
Certain facts respecting the tire, a Hercules Superior XII steel belted
radial, were either undisputed or conceded by respondents. First, while
the tire's installation date and service history are unknown, the tire had
been installed at the time Carmichael purchased the van. Second, the tire
had been driven for thousands of miles before the accident and the tread
had been reduced by wear from its original depth of 10/32 to 11/32 of an
inch to a depth of 0/32 to 3/32 of an inch. Third, the tire had been punctured
at some point in its service life and the exterior holes caused by the puncture
had not been adequately filled. Pet. App. 3b.
Carlson reached the conclusion, set out in deposition testimony and a subsequent
written report, that the tire was defective. In Carlson's opinion, the tire
on respondents' minivan failed because of insufficient adhesion between
the rubber, steel and nylon components of the tire. Pet. App. 8b. Carlson
stated that loss of adhesion can be caused either by abuse, such as when
the tire is underinflated or overloaded and thereby suffers "overdeflection,"
or by a manufacturing or design defect. Id. at 8b-9b. Carlson examines four
indicators for signs of overdeflection:
(1) greater tread wear on the shoulder than in the center of the tire; (2)
sidewall deterioration or discoloration; (3) abnormal bead grooving on the
tire; and (4) rim flange impressions.
Pet. App. 9b. Carlson explained that, if he fails to find sufficient evidence
of two of the four indicators in a tire, he rules out overdeflection as
a cause of tire failure and (unless there is evidence of some other form
of abuse) concludes that the loss of adhesion is the result of a manufacturing
or design defect. Id. at 9b.
Carlson examined photographs that Edwards had taken and made a visual inspection
of the tire on the morning of his deposition. Pet. App. 9b-10b & n.6.
He concluded that, while the tire showed signs of abuse under the four factors,
there was insufficient evidence to establish overdeflection. Id. at 10b.
He concluded, on that basis, that the tire was defective. In effect, "Carlson's
expert opinion that the tire failure was caused by a manufacturing or design
defect is founded on his determination that there is a paucity of evidence
of overdeflection or other abuse, rather than [on] his ability to pinpoint
any affirmative evidence of a defect." Id. at 10b.
3. The district court granted petitioners' motion to exclude Carlson's testimony
and, finding that respondents had no other evidence of defect, granted petitioners'
motion for summary judgment. Pet. App. 1b-22b. The district court assumed
for purposes of its analysis that Carlson is qualified as an expert on the
causes of tire failure, but it also concluded that the analytical framework
set out in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993),
applies to this case. Pet. App. at 8b, 11b. Noting Daubert's admonition
that district courts should serve as "gatekeepers" to evaluate
proposed expert testimony, the district court assessed the reliability of
Carlson's proposed testimony by looking at the considerations identified
by this Court in Daubert, including: (1) whether the technique or theory
may be tested or refuted; (2) whether the technique or theory has been a
subject of peer review or publication; (3) the known or potential rate of
error of a technique; and (4) the degree of acceptance of a theory or technique
within the relevant scientific community. Id. at 11b-16b. The court concluded
that Carlson's testimony, evaluated in light of those factors, does not
have sufficient evidentiary reliability to be admissible at trial. Ibid.
The court rejected respondents' contention that Daubert is inapplicable
because Carlson's testimony rests on a "technical," rather than
a "scientific" analysis. Id. at 16b-18b. Because Carlson's testimony
is the only basis for respondents' claim of defect in the tire, the court
granted petitioners' motion for summary judgment. Id. at 19b-22b.
4. On reconsideration, the district court reaffirmed its conclusion. Pet.
App. 1c-7c. In response to respondents' criticism that the court had simply
disagreed with Carlson's results, the court stated that it "no way
passed judgment on the validity of Carlson's conclusions," but "found
the methodological foundation of Carlson's testimony to be lacking."
Id. at 3c. The court also rejected respondents' contention that it had "convert[ed]
the flexible Daubert inquiry into a rigid one," explaining that while
"the list of criteria propounded in Daubert was intended neither to
be exhaustive nor to apply in every case," it had "found the Daubert
factors appropriate, analyzed them, and discerned no competing criteria
sufficiently strong to outweigh them." Id. at 4c. Finally, the court
rejected respondents' contention that Carlson's testimony met the elements
of "testability," peer review and general acceptance, noting that
respondents had failed to demonstrate that "the methodology and principles
adopted by Carlson are widely accepted in the relevant community."
Id. at 5c-6c.
5. The court of appeals reversed. Pet. App. 1a-10a. The court of appeals,
like the district court, assumed that Carlson was an expert qualified to
testify about the causes of tire failure. Id. at 3a n.2. The court of appeals
concluded, however, that the factors that Daubert had identified for evaluating
expert testimony apply only to testimony based on the "application
of scientific principles" and do not apply to Carlson's testimony,
which the court characterized as based on "skill- or experience-based
observation." Id. at 6a. See id. at 5a-8a. The court of appeals ruled
that the district court had erred as a matter of law by applying the Daubert
factors and remanded the case for a further hearing by the district court
"to determine if Carlson's testimony is sufficiently reliable and relevant
to assist a jury." Id. at 9a.
SUMMARY OF ARGUMENT
This Court's decision in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509
U.S. 579 (1993), establishes a general framework and identifies illustrative
factors for resolving whether expert testimony is admissible under Rule
702 of the Federal Rules of Evidence. The court of appeals concluded that
Daubert does not apply to the expert testimony at issue here and that the
district court therefore erred as a matter of law in applying the factors
identified in Daubert to determine whether Carlson's expert testimony is
admissible. We submit, to the contrary, that the district court did not
abuse its discretion in considering those factors in the course of determining
the reliability of Carlson's methodology.
A. This Court's decision in Daubert holds, as a general principle, that
a trial judge must ensure "that an expert's testimony both rests on
a reliable foundation and is relevant to the task at hand." 509 U.S.
at 597. In addition, the Court's decision provides specific guidance with
respect to the trial judge's screening of "expert scientific testimony."
Id. at 592-595. The Court recognized that "many factors" may bear
on the inquiry, but it nevertheless highlighted four factors, relating to
verification, publication, normalization, and acceptance within the relevant
discipline, that a court may consider in evaluating the reliability of expert
scientific testimony. The Court emphasized, however, that the inquiry envisioned
by Rule 702 is "a flexible one." The Court made clear that the
specific factors that it identified were intended as guides that may apply
in a range of circumstances.
B. The court of appeals erroneously concluded that this Court's decision
in Daubert applies only to expert testimony that is based on "the application
of scientific principles" and not to expert testimony based on "skill-
or experience-based observation." Pet. App. 6a. Daubert's general framework
for analyzing expert testimony, which requires the trial judge to ensure
that expert opinion is reliable and relevant, applies to all expert testimony,
and not simply to "scientific" testimony. The court of appeals
also erred in drawing a categorical line, for purposes of applying the factors
identified in Daubert, between testimony that relies on "scientific
principles" and testimony that relies on "skill- or experience-based
observations." Science can utilize both deductive and inductive methodologies,
and each is subject to scientific methods of validation. Even if "scientific"
evidence could be categorically distinguished from "non-scientific"
evidence on the basis the court of appeals suggests, the court's blanket
rule prohibiting application of the factors identified in Daubert to testimony
based on "skill- or experience-based observation" would unduly
limit the discretion of trial judges, who should have considerable latitude
to determine what factors are germane in assessing the reliability and relevance
of particular instances of expert testimony.
C. The district court did not abuse its discretion in applying the factors
that this Court identified in Daubert to the expert testimony at issue in
this case. The court was entitled to consider those factors here because
they provide a rational basis for assessing whether the expert's methodology
is reliable in drawing from his observations inferences as to the cause
of the tire's failure. The district court appropriately considered those
factors, as well as other pertinent factors, and reasonably concluded that
the expert's methodology "is simply too unreliable, too speculative,
and too attenuated to the scientific knowledge on which it is based to be
of material assistance to the trier of fact." Pet. App. 18b. The district
court's decision rests on a reasonable exercise of discretion, and the court
of appeals consequently erred in overturning the district court's judgment.
ARGUMENT
THE COURT OF APPEALS ERRED IN SETTING ASIDE THE DISTRICT COURT'S DETERMINATION
THAT THE TESTIMONY OF RESPONDENTS' EXPERT IS NOT ADMISSIBLE UNDER RULE 702
OF THE FEDERAL RULES OF EVIDENCE
Petitioners have characterized the issue here as whether a trial court may
consider the factors set out in Daubert v. Merrell Dow Pharmaceuticals,
Inc., 509 U.S. 579 (1993), in a Rule 702 analysis of the admissibility of
"an engineering expert's testimony." Pet. i. The court of appeals'
decision is mistaken, however, for reasons apart from the particular professional
identity of the expert. The court of appeals drew a categorical distinction,
for purposes of applying Daubert vel non, between expert testimony based
on "application of scientific principles" and expert testimony
based on "skill- or experience-based observations." Pet. App.
6a. The court erred in drawing that distinction. A trial court has substantial
discretion to employ the factors set out in Daubert, as well as other pertinent
factors, so long as the factors rationally bear on the trial court's determination,
under Rule 702, of whether the expert's testimony is reliable and relevant.
The trial court did not abuse its discretion in employing the Daubert factors
or in reaching its ultimate conclusion to exclude the expert's testimony
in this case.
A. This Court's Decision in Daubert Provides A General Framework And Identifies
Potentially Pertinent Factors For Determining Whether Expert Testimony Is
Admissible Under Rule 702
Article VII of the Federal Rules of Evidence sets out a series of Rules
addressing the use of opinions and expert testimony at trial. Rule 701 states
the traditional limitation that a person who is not an "expert"
may testify in the form of opinions or inferences only to the extent that
those opinions or inferences are rationally based on the perception of the
witness and are helpful to a clear understanding of the witness's testimony
or the determination of a fact in issue. See Fed. R. Evid. 701. Rule 702
creates much wider latitude for an expert to testify in the form of opinion,
stating:
If scientific, technical, or other specialized knowledge will assist the
trier of fact to understand the evidence or to determine a fact in issue,
a witness qualified as an expert by knowledge, skill, experience, training
or education, may testify thereto in the form of an opinion or otherwise.
Fed. R. Evid. 702. Rule 703 further provides that the facts or data upon
which the expert relies may be those perceived by or made known to the expert
at or before the hearing and, if they are of a type reasonably relied upon
by experts in the particular field, those facts or data need not be admissible
in evidence. Fed. R. Evid. 703. See also Fed. R. Evid. 704 (governing opinions
on ultimate issues); Fed. R. Evid. 705 (governing disclosure of underlying
facts or data); Fed. R. Evid. 706 (governing court-appointed experts).
This Court's decision in Daubert lays out a general framework for applying
Rule 702, which "clearly contemplates some degree of regulation of
the subjects and theories about which an expert may testify." Daubert,
509 U.S. at 589. The Court concluded that Rule 702 requires the trial court
to screen expert testimony to protect the jury from expert opinions that
do not satisfy the threshold requirements of "evidentiary reliability"
and "relevance" to the issues before the trier of fact. Id. at
589-591. The Court specifically held that trial judges must ensure "that
an expert's testimony both rests on a reliable foundation and is relevant
to the task at hand." Id. at 597. Accord General Electric Co. v. Joiner,
118 S. Ct. 512, 517 (1997) ("the Federal Rules of Evidence * * * leave
in place the 'gatekeeper' role of the trial judge in screening such evidence").
The Court's decision in Daubert also provides specific guidance with respect
to the trial court's screening of "expert scientific testimony."
509 U.S. at 592-595. The Court stated that the trial court must determine
at the outset, pursuant to Federal Rule of Evidence 104(a) (which describes
the trial judge's role in deciding preliminary evidentiary questions), "whether
the expert is proposing to testify to (1) scientific knowledge that (2)
will assist the trier of fact to understand or determine a fact in issue."
Daubert, 509 U.S. at 592. "This entails a preliminary assessment of
whether the reasoning or methodology underlying the testimony is scientifically
valid and of whether that reasoning or methodology properly can be applied
to the facts in issue." Id. at 592-593. The Court stated that "[m]any
factors will bear on the inquiry, and we do not presume to set out a definitive
checklist or test." Id. at 593. Nevertheless, the Court made some "general
observations" to provide guidance. Ibid.
The Court described four criteria or factors that are likely to be of assistance
to a trial court in evaluating whether the "theory or technique"
at issue is "scientific knowledge that will assist the trier of fact,"
Daubert, 509 U.S. at 593. Those factors are whether the theory or technique
(1) "can be (and has been) tested"; (2) "has been subjected
to peer review and publication"; (3) is subject to professional "standards"
and has "a known or potential rate of error"; and (4) has received
"acceptance" in the scientific community. Id. at 593-594. The
Court emphasized, however, that the "inquiry envisioned by Rule 702"
is "a flexible one." Id. at 594. "Its overarching subject
is the scientific validity--and thus the evidentiary relevance and reliability-of
the principles that underlie a proposed submission. The focus, of course,
must be solely on principles and methodology, not on the conclusions that
they generate." Id. at 594-595. The Court's decision in Daubert accordingly
makes clear that the specific factors that the Court identified are guideposts
that may apply in a range of circumstances, but do not encompass every situation
in which an expert may testify.
B. The Court of Appeals Erred In Holding That This Court's Decision In Daubert
Does Not Apply to Expert Testimony That Is Based On "Skill- or Experience-Based
Observation"
The court of appeals concluded that this Court's decision in Daubert resolved
only the question of admission of expert testimony in the "scientific
context." Pet. App. 5a. Based on that understanding, the court of appeals
drew a categorical distinction between "an expert who relies on the
application of scientific principles" and one who relies "on skill-
or experience-based observation," as the basis for an expert opinion.
Id. at 6a. Applying that distinction to this case, the court determined
that Carlson's testimony is "non-scientific" because "Carlson
rests his opinion on his experience in analyzing failed tires." Id.
at 8a. The court accordingly ruled that "Carlson's testimony falls
outside the scope of Daubert and that the district court erred as a matter
of law by applying Daubert to this case." Ibid.
As an initial matter, the court of appeals' understanding that Daubert applies
only to "scientific" evidence is flawed. This Court stated in
the course of its analysis that "[o]ur discussion is limited to the
scientific context because that is the nature of the expertise offered here."
Daubert, 509 U.S. at 590 n.8. Although the Court limited its discussion
in that way, the Court articulated certain basic principles for applying
Rule 702 to all forms of expert testimony. The Court ruled that a trial
judge must ensure that "an expert's testimony both rests on a reliable
foundation and is relevant to the task at hand." Id. at 597. The rationale
for the Court's ruling-that Rule 702 "clearly contemplates some degree
of regulation of the sub- jects and theories about which an expert may testify"-logically
applies to all manner of expert testimony, regardless of whether the testimony
is based on "scientific, technical, or other specialized knowledge."
Fed. R. Evid. 702.1
Daubert recognizes that Rule 702 allows the admission of expert testimony-whether
based on "scientific, technical, or other specialized knowledge"-
if it "will assist the trier of fact" (Fed. R. Evid. 702). See
Daubert, 509 U.S. at 589, 591. Daubert also recognizes that Rule 702 prohibits
the admission of expert testimony, whatever its basis, if the testimony
does not satisfy the basic thresholds of reliability and relevance that
are essential for the testimony to be useful in the trial setting. See id.
at 590-592. Daubert provides no reason for subjecting expert opinions to
different formulations of that fundamental threshold test depending on whether
the opinions are based on "scientific," "technical,"
or "other specialized" knowledge. See id. at 592 ("relaxation
of the usual requirement of firsthand knowledge * * * is premised on an
assumption that the expert's opinion will have a reliable basis in the knowledge
and experience of his discipline"). The court of appeals implicitly
recognized that point (without attribution to Daubert) by acknowledging
that "it is the district court's duty to determine if Carlson's testimony
is sufficiently reliable and relevant to assist a jury." Pet. App.
9a (citing United States v. 14.38 Acres of Land, 80 F.3d 1074, 1078 (5th
Cir. 1996)).2
The court of appeals' disagreement with the district court therefore rests,
not so much on whether to apply "Daubert's reliability framework,"
Pet. App. 4a, but on whether the district court was entitled to consider
the four particular factors that the Court identified in Daubert as indicia
of evidentiary reliability. See p. 12, supra. But even in that limited sense,
the court of appeals' decision is unsound. The court of appeals is correct
that this Court discussed those factors-which may be conveniently described
as verification, publication, normalization, and acceptance--in the context
of "a proffer of expert scientific testimony." Daubert, 509 U.S.
at 592. The court of appeals is nevertheless mistaken in ruling that there
is a categorical distinction, for purposes of applying those factors, between
expert testimony based on "application of scientific principles"
and expert testimony based on "skill- or experience-based observation."
Pet. App. 6a.
As this Court recognized in Daubert, Rule 702's reference to "scientific"
knowledge "implies a grounding in the methods and procedures of science."
509 U.S. at 590. The term "science" is commonly understood to
describe "a process for proposing and refining theoretical explanations
about the world that are subject to further testing and refinement."
Ibid., quoting Brief for American Association for the Advancement of Science
et al. as Amicus Curiae 7-8 (emphasis in original). The court of appeals
is assuredly correct that scientific opinion may be based on deductive reasoning
from known "scientific principles." See IV Oxford English Dictionary
358 (2d ed. 1989) (defining "deduction" as "[t]he process
of deducing or drawing a conclusion from a principle already known or assumed.").
But scientific opinion may also be based on inductive reasoning from observation
of the physical world. See VII Oxford English Dictionary 890 (2d ed. 1989)
(defining "induction" as the "[t]he process of inferring
a general law or principle from the observation of particular instances.").3
The court of appeals is accordingly mistaken in suggesting that Daubert's
reference to "scientific" testimony necessarily limits Daubert's
reach to testimony based on "application of scientific principles,"
but not to any testimony based on "skill- or experience-based observation."
Nothing in Daubert supports the creation of such a dichotomy, for purposes
of applying Rule 702, between scientific knowledge based on deductive reasoning
and scientific knowledge based on inductive reasoning. Either methodology
can produce expert scientific testimony. In either case, the reliability
of the testimony can be evaluated by reference to its scientific validity.
See Daubert, 509 U.S. at 590 & n.9. This is not to say, of course, that
every instance of deduction or induction is an exercise in science. The
point is simply that the court of appeals erred in suggesting that testimony
based on "skill- or experience-based observation" is inherently
"non-scientific." Pet. App. 6a.
Even if there were a theoretical basis, derived from the definition of "science,"
for holding that expert opinions based on "skill- or experience-based
observation" are inherently "non-scientific," Pet. App. 6a,
it would make no sense to hamstring trial judges with definitive rules respecting
what factors they may consider for "scientific" as compared to
"non-scientific" expert testimony. As this Court recognized in
Daubert, the fundamental inquiry for the trial judge under Rule 702 is whether
the expert's testimony "rests on a reliable foundation and is relevant
to the task at hand." 509 U.S. at 597. The Court noted that "[m]any
factors will bear on the inquiry," and it did "not presume to
set out a definitive checklist or test." Id. at 593. The Court's "general
observations" respecting the four factors identified in Daubert simply
provide illustrative examples of pertinent considerations and are not meant
to displace the trial judge's traditional discretion to determine what factors
are germane in a particular case. See id. at 593-594.4
Given the complexity of modern society and the specialization of roles within
a culture, litigants are likely to call upon a wide spectrum of experts
possessing "knowledge" that may "assist the trier of fact
to understand the evidence or to determine a fact in issue." Fed. R.
Evid. 702.5 In all such cases, the trial judge must find that the testimony
is properly grounded, well-reasoned, and not speculative. The factors identified
in Daubert may or may not be pertinent in assessing reliability, depending
on the nature of the issue, the expert's particular expertise, and the subject
of his testmony. It is simply not feasible to categorize definitively what
factors the court may consider for each species of expert. As the Court
emphasized in Daubert, Rule 702 envisions a "flexible" inquiry,
id. at 594, and trial courts should therefore have substantial latitude
in determining what criteria or factors are germane in assessing the evidentiary
reliability of particular expert testimony.6
As this Court made clear in General Electric v. Joiner, the trial court's
determinations under Rule 702 should be set aside only upon a showing that
the court abused its discretion. 118 S. Ct. at 517-519. That standard applies,
as well, to the trial court's determination of what factors appropriately
bear on the inquiry in the particular circumstances. As we explained in
greater detail in our amicus brief in General Electric (see U.S. Amicus
Br. 17-23), appellate review under the abuse of discretion standard is not
"an empty exercise." Koon v. United States, 518 U.S. 81, 98 (1996).
It encompasses both errors of law and errors of fact. See Cooter & Gell
v. Hartmarx Corp., 496 U.S. 384, 399-405 (1990). A district court may abuse
its discretion by failing to exercise discretion, by applying inappropriate
analytical criteria, or by exceeding the range of permissible choice. See
generally Koon, 518 U.S. at 98- 100; Cooter & Gell, 496 U.S. at 399-405;
Pierce v. Underwood, 487 U.S. 552, 570 (1988); United States v. Dockery,
955 F.2d 50, 54 (D.C. Cir. 1992). Depending on the expert testimony involved,
a district court's decision to apply the factors identified in Daubert,
or not to apply those factors, could result in an abuse of discretion. The
crucial question in each case is whether the district court has properly
assessed the reliability of the expert's testimony in light of the facts
at issue and the expertise involved.7
The court of appeals' unqualified conclusion that the district court erred
"as a matter of law" by applying the factors identified in Daubert
to expert testimony based on "skill- or experience-based observation"
(Pet. App. 8a, 10a) is especially problematic when viewed in light of the
need for a trial court to exercise sound discretion based on the reliability
and relevance of particular expert testimony in a specific case. The court
of appeals has effectively created a categorical rule that a district court
can never apply the factors specified in Daubert to expert testimony that
rests on what the court of appeals calls "skill- or experience-based
observation." There is no warrant for such a rule. In many cases, some
or all of the factors identified in Daubert-verification, publication, normalization,
and acceptance in the relevant field--may be germane, depending on the circumstances,
in assessing the reliability of testimony based on "skill- or experience-based
observations." The court of appeals is wrong in suggesting that the
factors identified in Daubert can never prove useful in resolving the reliability
of such testimony.8
C. The District Court Did Not Abuse Its Discretion In Applying the Factors
Identified In Daubert To the Expert Testimony In This Case Or In Reaching
Its Ultimate Conclusion That The Testimony Should Be Excluded
Under this Court's decision in General Electric, it would have been proper
for the court of appeals to reverse the district court's decision to exclude
Carlson's testimony if the district court had abused its discretion in concluding
that the testimony lacks sufficient reliability to assist the trier of fact.
118 S. Ct. at 515, 519. The district court, however, did not abuse its discretion.
The district court understood that its duty as "gatekeeper" required
it to evaluate whether the knowledge and experience on which Carlson relied
is sufficiently trustworthy and whether Carlson has reliably applied that
knowledge and experience to the facts of this case. Pet. App. 11b-12b &
n.7, 18b, 6c, 4c-7c. The district court properly concluded, based on the
factors identified in Daubert and other pertinent considerations, that Carlson's
methodology is not sufficiently reliable, as to the specific question of
whether the tire at issue was defective, to provide the basis for admissible
testimony. See Pet. App. 18b, 7c.9
As the district court explained, "Carlson's expert opinion that the
tire failure was caused by a manufacturing or design defect is founded on
his determination that there is a paucity of evidence of overdeflection
or other abuse, rather than [on] his ability to pinpoint any affirmative
evidence of a defect." Pet. App. 10b. The district court questioned
Carlson's method of inferring a defect from the absence of indicia of abuse,
and it acted within its discretion in considering the factors cited in Daubert
to test the reliability of Carlson's methodology. The district court was
entitled to consider those factors in this case because they provide a reasonable
basis for assessing whether Carlson's methodology is valid.
Carlson propounds a methodology to assess the cause of a tire failure.10
Methodologies for determining the cause of physical events are typically
subject to validation. Respondents have conceded that, as a practical matter,
the factors identified in Daubert for validating scientific theories of
causation can be applied to Carlson's methodology. See Pet. App. 5c.; Memorandum
of Law in Support of Plaintiff's Motion for Reconsideration 14 ("Reconsideration
will show that the testimony was admissible because it was based on refutable
techniques which were subject to peer review and were widely accepted in
the relevant scientific community."). Those factors shed light on the
reliability of Carlson's methods, because his methods are more trustworthy
if they have been validated through testing, through publication and peer
review, through quantitative assessment of their rate of error, and through
their acceptance or rejection by those who have a stake in the reliability
of the results. The factors that the Court identified in Daubert are therefore
germane to the court's Rule 702 inquiry. See Pet. App. 4c.
In applying those factors, the district court found that Carlson described
his methodology as "subjective," and he could not identify any
tests or other procedures to corroborate or refute his results. Pet. App.
12b-13b, 5c. The district court also found that no publications approved
or discussed Carlson's techniques for tire failure analysis and that the
publications that do discuss tire testing "do not back his techniques."
Id. at 13b-14b, 5c-6c. The district court determined that the rate of error
that would result from using Carlson's methodology is unknown. Id. at 14b-15b,
5c n.2. Carlson did not know whether his previous analyses of failed tires
were correct or incorrect, and there was no evidence that anyone had ever
tested Carlson's methods in a controlled setting to gauge their accuracy.
Id. at 14b-15b. Finally, the court concluded that there was no evidence
that "the relevant scientific community accepts a visual-inspection,
process-of-elimination analysis of tire failure in the manner * * * performed
by Carlson." Id. at 15b-16b, 6c-7c.
The district court assessed Carlson's testimony against the reliability
indicia discussed in Daubert, but it also recognized that the reliability
inquiry is a "flexible" one and that the "list of criteria
propounded in Daubert was intended neither to be exhaustive nor to apply
in every case." Pet. App. 4c. The court gave respondents the opportunity
to show that other factors not discussed in Daubert demonstrate the reliability
of Carlson's methods. Id. at 3c-4c & n.1. The court found, however,
that respondents had identified "no countervailing factors operating
in favor of admissibility which could outweigh those identified in Daubert."
Id. at 4c. Thus, the district court did not blindly or inaptly apply this
Court's "observations" in Daubert to this case. Rather, as the
court stated, it "found the Daubert factors appropriate, analyzed them,
and discerned no competing criteria sufficiently strong to outweigh them."
Ibid.
The district court's assessment properly focused on the reliability of Carlson's
methodology. Pet. App. 6c. The court specifically noted that it saw no inherent
flaw in the use of a process-of-elimination technique to prove causation,
provided that the underlying methodology for eliminating potential causes
is reliable. Id. at 11b n.7. It concluded, however, that Carlson's methodology
is not reliable because it is based on a largely "subjective"
process lacking any independent indicia of trustworthiness. Id. at 12b-15b,
5c-6c. Carlson's testimony is "simply too unreliable, too speculative,
and too attenuated to the scientific knowledge on which it is based to be
of material assistance to the trier of fact." Id. at 18b.
At bottom, the district court excluded Carlson's testimony because it could
find no foundation for Carlson's methodology beyond Carlson's subjective
assurances that his method for determining the cause of tire failure is
reliable. As this Court made clear in General Electric, "nothing in
either Daubert or the Federal Rules of Evidence requires a district court
to admit opinion evidence which is connected to existing data only by the
ipse dixit of the expert." 118 S. Ct. at 519. A proffered expert, such
as Carlson, who relies on experience as a basis for testimony must be able
to explain, step-by-step, how that experience reliably leads to the conclusions
reached. See Daubert v. Merrell Dow Pharmaceuticals, Inc., 43 F.3d at 1319;
In re Paoli R.R. Yard PCB Litigation, 35 F.3d 717, 745 (3d Cir. 1994), cert.
denied, 513 U.S. 1190 (1995).11
In sum, the district court "found the methodological foundation of
Carlson's testimony to be lacking, and excluded his testimony on that basis,
in accordance with Rule 702." Id. at 3c. The district court's decision
rests on a reasonable exercise of discretion in applying the pertinent legal
standards, and the court of appeals consequently erred in overturning the
district court's judgment.12
CONCLUSION
The judgment of the court of appeals should be reversed.
Respectfully submitted.
SETH P. WAXMAN
Solicitor General
FRANK W. HUNGER
Assistant Attorney General
LAWRENCE G. WALLACE
Deputy Solicitor General
JEFFREY P. MINEAR
Assistant to the Solicitor
General
ANTHONY J. STEINMEYER
JOHN P. SCHNITKER
Attorneys
AUGUST 1998
1 The Advisory Committee Note accompanying Rule 702 supports that understanding.
As the Advisory Committee Note explains:
The rule is broadly phrased. The fields of knowledge which may be drawn
upon are not limited merely to the "scientific" and "technical"
but extend to all "specialized" knowledge. Similarly, the expert
is viewed, not in a narrow sense, but as a person qualified by "knowledge,
skill, experience, training or education." Thus, within the scope of
the rule are not only experts in the strictest sense of the word, e.g.,
physicians, physicists, and architects, but also the large group sometimes
called "skilled" witnesses, such as bankers or landowners testifying
to land values.
Nothing in Rule 702 suggests that the need for "some degree of regulation
of the subjects and theories about which an expert may testify" applies
to some of those experts, but not others.
2 Distinguishing between categories of experts for purposes of Rule 702
would pose serious practical problems. As this Court observed in Daubert,
the law "must resolve disputes finally and quickly." 509 U.S.
at 597. The evaluation of expert testimony in the course of resolving legal
disputes would be difficult to manage if different standards governed the
admissibility of different categories of experts. When making "swift
battlefield decisions on tangled evidentiary matters," United States
v. Sepulveda, 15 F.3d 1161, 1183-1184 (1st Cir. 1993), cert. denied, 512
U.S. 1223 (1994), both district courts and trial counsel benefit from reliance
on a single conceptual framework for assessing the admissibility of the
proffered testimony. See American College of Trial Lawyers, Standards and
Procedures For Determining The Admissibility of Expert Evidence After Daubert,
157 F.R.D. 571, 577-578 (1994). There is, accordingly, a strong need for
one general framework when evaluating the admissibility of expert testimony
and evidence under Rule 702.
3 As Albert Einstein observed, "[t]he whole of science is nothing more
than a refinement of everyday thinking." Albert Einstein, Ideas and
Opinions 290 (1982). He described the relationship of induction and deduction
as follows:
The theorist's method involves his using as his foundation general postulates
or "principles" from which he can deduce conclusions. His work
thus falls into two parts. He must first discover his principles and then
draw the conclusions which follow from them. * * * The scientist has to
worm the[] general principles out of nature by perceiving in comprehensive
complexes of empirical facts certain general features which permit of precise
formulation.
Once this formulation is successfully accomplished, inference follows on
inference, often revealing unforeseen relations which extend far beyond
the province of the reality from which the principles were drawn. But as
long as no principles are found on which to base the deduction, the individual
empirical fact is of no use to the theorist; indeed he cannot even do anything
with isolated general laws abstracted from experience. He will remain helpless
in the face of separate results of empirical research, until principles
which he can make the basis of deductive reasoning have revealed themselves
to him.
Id. at 221. Sir Isaac Newton expressed a similar view, stating, when defending
his theory of refraction, "[f]or the best and safest method of philosophizing
seems to be, first to inquire diligently into the properties of things,
and establishing those properties by experiments and then to proceed more
slowly to hypotheses for the explanation of them." Isaac Newton, Papers
and Letters on Natural Philosophy 106 (I. Bernard Cohen ed., 1958) (translated
from the Latin). The scientist's methodology in making observations and
formulating general principles, no less than his methodology for extending
those principles to other situations, is subject to scientific validation.
4 For example, other relevant inquiries, depending on the circumstances,
may include whether the expert's opinion was developed solely for purposes
of litigation as a "hired gun," Watkins v. Telsmith, Inc., 121
F.3d 984, 991 (5th Cir. 1997); Daubert v. Merrell Dow Pharmaceuticals, Inc.,
43 F.3d 1311, 1317 (9th Cir. 1995); whether the expert, purporting to apply
an accepted methodology, presents a conclusion shared by no other expert
in the field, Lust v. Merrell Dow Pharmaceuticals, Inc., 89 F.3d 594, 598
(9th Cir. 1996); whether an analytical gap exists between the expert's premises
and the expert's conclusions, General Electric, 118 S. Ct. at 519; Turpin
v. Merrell Dow Pharmaceuticals, Inc., 959 F.2d 1349, 1360 (6th Cir.), cert.
denied, 506 U.S. 826 (1992); and whether the discipline or field at issue
generally lacks reliability as a matter of law, see Bradley v. Brown, 42
F.3d. 434, 438 (7th Cir. 1994); Viterbo v. Dow Chemical, 826 F.2d 420, 422-424
(5th Cir. 1987); Frank v. New York, 972 F. Supp. 130, 136-137 (N.D.N.Y.
1997).
5 The case law offers numerous and varied examples of such expertise. See,
e.g., United States v. Griffith, 118 F.3d 318, 322-323 (5th Cir. 1997) (drug
terms); United States v. Jones, 107 F.3d 1147, 1160-1161 (6th Cir. 1997)
(handwriting analysis); United States v. Cordoba, 104 F.3d 225, 229-230
(9th Cir. 1997) (criminal modus operandi); United States v. 14.38 Acres
of Land, 80 F.3d 1074, 1077-1079 (5th Cir. 1996) (land valuation); United
States v. Kunzman, 54 F.3d 1522, 1530 (10th Cir. 1995) (check marking identification);
United States v. Johnson, 28 F.3d 1487, 1496-1498 (8th Cir. 1994) (drug
trafficking operations); United States v. Sylvester, 848 F.2d 520, 522 (5th
Cir. 1988) (agricultural practices); Eckert v. Aliquippa & S. R.R.,
828 F.2d 183, 185n.5 (3d Cir. 1987) (railroad procedures); United States
v. Riccobene, 709 F.2d 214, 230 (3d Cir.) (organized crime jargon), cert.
denied, 464 U.S. 849 (1983); Chrysler Credit Corp. v. Whitney National Bank,
824 F. Supp. 587, 601 (E.D. La. 1993) (commercial lending practices); Arrow,
Edelstein & Gross, P.C. v. Rosco Prod., Inc., 581 F. Supp. 520, 523-524
(S.D.N.Y. 1984) (attorneys' fee valuation).
6 In the exercise of its gatekeeping duties, the district court may, of
course, admit testimony from experts who are not scientists and whose specialized
knowledge is not amenable to scientific measures of reliability. Genuine
expertise may be based on practical experience in a particular field, and
the "measure of intellectual rigor will vary by the field of expertise."
Tyus v. Urban Search Management, 102 F.3d 256, 263 (7th Cir. 1996). If the
testimony in such cases is both reliable and relevant, it is admissible.
See generally E. Imwinkelried, The Next Step After Daubert: Developing A
Similarly Epistemological Approach To Ensuring The Reliability Of Nonscientific
Expert Testimony, 15 Cardozo L. Rev. 2271 (1994).
7 It bears emphasis, moreover, that the trial court must be mindful that
its role is to assess the reliability, and not the credibility, of the expert's
testimony. Daubert, 509 U.S. at 595.
8 For example, the court of appeals supported its result by offering the
hypothetical case of "an experienced mechanic" who "may recognize
patterns of normal and abnormal wear on a [spark plug] even though he has
no knowledge of the general principles of physics or chemistry that might
explain why or how a spark plug works." Pet. App. 7a n.6. The mere
fact that the mechanic purports to be "experienced" does not,
however, immunize the mechanic's testimony from the threshold inquiry under
Rule 702 of whether it is sufficiently reliable and relevant to be put before
a jury. See General Electric, 118 S. Ct. at 519 ("nothing in either
Daubert or the Federal Rules of Evidence requires a district court to admit
opinion evidence which is connected to existing data only by the ipse dixit
of the expert"). In resolving a challenge to the mechanic's testimony
under Rule 702, a trial court should not be precluded from considering the
factors identified in Daubert if they are reasonable measures of the reliability
of the testimony. For example, a district court could consider whether the
inferences drawn by the auto mechanic on the basis of "skill-or experience-based
observations" have been reached by means that have been validated through
industry tests or studies, find support in auto repair publications, or
are widely accepted in the automotive repair industry. See, e.g., Mike Forsythe
& John H. Haynes, The Haynes Chrysler Engine Overhaul Manual 3-3 to
3-5 (1994) (illustrating and explaining patterns of sparkplug wear); Chilton's
Easy Car Care 148-150 (2d ed. 1985) (same). The court of appeals is mistaken
in suggesting that consideration of those factors, which mirror the factors
identified in Daubert, would necessarily result in reversible error "as
a matter of law."
9 The trial court did not consider whether Carlson could have testified
as an expert on other matters respecting the tire. Respondents had relied
solely on Carlson's testimony to establish that the tire was defective,
which is an essential element of their case. If the trial court was correct
in determining that Carlson's testimony was inadmissible for that purpose,
then it correctly ruled that petitioners were entitled to summary judgment
and any other evidentiary issues are moot.
10 In this respect, Carlson's proffered testimony differs significantly
from the court of appeals' analogy to "a beekeeper who claims to have
learned through years of observation that his charges always take flight
into the wind" (Pet. App. 8a). Determining the cause of the bees' behavior
(instinct, training, trial and error, etc.) would require the use of methodology
to draw further inferences.
11 Indeed, it would seem "exactly backwards that experts who purport
to rely on general * * * principles and practical experience might escape
screening by the district court simply by stating that their conclusions
were not reached by any particular method or technique." Watkins, 121
F.3d at 991.
12 We note that the Standing Committee on Rules and Practice of the Judicial
Conference of the United States has recently proposed amendments to Rule
702 that would specify that an expert's testimony would be admissible only
if "(1) the testimony is sufficiently based upon reliable facts or
data, (2) the testimony is the product of reliable principles and methods,
and (3) the witness has applied the principles and methods reliably to the
facts of the case." Preliminary Draft of Proposed Amendments to the
Federal Rules of Civil Procedure and Evidence: Request For Comment 122 (August
1998).