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| [1] | United States Supreme Court |
| [2] | No. 97-1709 |
| [3] | 526 U.S. 137, 119 S.Ct. 1167, 143 L.Ed.2d 238, 1999.SCT.42055 <http://www.versuslaw.com>,
50 U.S.P.Q.2d 1177, 67 USLW 4179, 99 Cal. Daily Op. Serv. 2059 |
| [4] | March 23, 1999 |
| [5] | KUMHO TIRE COMPANY, LTD., ET AL., PETITIONERS V. PATRICK CARMICHAEL, ETC.,
ET AL. |
| [6] | SYLLABUS BY THE COURT |
| [7] | Syllabus |
| [8] | OCTOBER TERM, 1998 |
| [9] | KUMHO TIRE CO. v. CARMICHAEL |
| [10] | 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. |
| [11] | SUPREME COURT OF THE UNITED STATES |
| [12] | KUMHO TIRE CO., LTD., et al. v. CARMICHAEL et al. |
| [13] | Certiorari To The United States Court Of Appeals For The Eleventh Circuit |
| [14] | No. 97-1709. |
| [15] | Argued December 7, 1998 |
| [16] | Decided March 23, 1999 |
| [17] | When a tire on the vehicle driven by Patrick Carmichael blew out and the
vehicle overturned, one passenger died and the others were injured. The
survivors and the decedent's representative, respondents here, brought this
diversity suit against the tire's maker and its distributor (collectively
Kumho Tire), claiming that the tire that failed was defective. They rested
their case in significant part upon the depositions of a tire failure analyst,
Dennis Carlson, Jr., who intended to testify that, in his expert opinion,
a defect in the tire's manufacture or design caused the blow out. That opinion
was based upon a visual and tactile inspection of the tire and upon the
theory that in the absence of at least two of four specific, physical symptoms
indicating tire abuse, the tire failure of the sort that occurred here was
caused by a defect. Kumho Tire moved to exclude Carlson's testimony on the
ground that his methodology failed to satisfy Federal Rule of Evidence 702,
which says: "If scientific, technical, or other specialized knowledge
will assist the trier of fact ... , a witness qualified as an expert ...
may testify thereto in the form of an opinion." Granting the motion
(and entering summary judgment for the defendants), the District Court acknowledged
that it should act as a reliability "gatekeeper" under Daubert
v. Merrell Dow Pharmaceuticals, Inc., 509 U. S. 579, 589, in which this
Court held that Rule 702 imposes a special obligation upon a trial Judge
to ensure that scientific testimony is not only relevant, but reliable.
The court noted that Daubert discussed four factors -- testing, peer review,
error rates, and "acceptability" in the relevant scientific community
-- which might prove helpful in determining the reliability of a particular
scientific theory or technique, id., at 593-594, and found that those factors
argued against the reliability of Carlson's methodology. On the plaintiffs'
motion for reconsideration, the court agreed that Daubert should be applied
flexibly, that its four factors were simply illustrative, and that other
factors could argue in favor of admissibility. However, the court affirmed
its earlier order because it found insufficient indications of the reliability
of Carlson's methodology. In reversing, the Eleventh Circuit held that the
District Court had erred as a matter of law in applying Daubert. Believing
that Daubert was limited to the scientific context, the court held that
the Daubert factors did not apply to Carlson's testimony, which it characterized
as skill- or experience-based. |
| [18] | Held: |
| [19] | 1. The Daubert factors may apply to the testimony of engineers and other
experts who are not scientists. Pp. 7-13. |
| [20] | (a) The Daubert "gatekeeping" obligation applies not only to
"scientific" testimony, but to all expert testimony. Rule 702
does not distinguish between "scientific" knowledge and "technical"
or "other specialized" knowledge, but makes clear that any such
knowledge might become the subject of expert testimony. It is the Rule's
word "knowledge," not the words (like "scientific")
that modify that word, that establishes a standard of evidentiary reliability.
509 U. S., at 589-590. Daubert referred only to "scientific" knowledge
because that was the nature of the expertise there at issue. Id., at 590,
n. 8. Neither is the evidentiary rationale underlying Daubert's "gatekeeping"
determination limited to "scientific" knowledge. Rules 702 and
703 grant all expert witnesses, not just "scientific" ones, testimonial
latitude unavailable to other witnesses on the assumption that the expert's
opinion will have a reliable basis in the knowledge and experience of his
discipline. Id., at 592. Finally, it would prove difficult, if not impossible,
for Judges to administer evidentiary rules under which a "gatekeeping"
obligation depended upon a distinction between "scientific" knowledge
and "technical" or "other specialized" knowledge, since
there is no clear line dividing the one from the others and no convincing
need to make such distinctions. Pp. 7-9. |
| [21] | (b) A trial Judge determining the admissibility of an engineering expert's
testimony may consider one or more of the specific Daubert factors. The
emphasis on the word "may" reflects Daubert's description of the
Rule 702 inquiry as "a flexible one." 509 U. S., at 594. The Daubert
factors do not constitute a definitive checklist or test, id., at 593, and
the gatekeeping inquiry must be tied to the particular facts, id., at 591.
Those factors 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 testimony. Some of those factors may be helpful in evaluating the
reliability even of experience-based expert testimony, and the Court of
Appeals erred insofar as it ruled those factors out in such cases. In determining
whether particular expert testimony is reliable, the trial court should
consider the specific Daubert factors where they are reasonable measures
of reliability. Pp. 10-12. |
| [22] | (c) The court of appeals must apply an abuse-of-discretion standard when
it reviews the trial court's decision to admit or exclude expert testimony.
General Electric Co. v. Joiner, 522 U. S. 136, 138-139. That standard applies
as much to the trial court's decisions about how to determine reliability
as to its ultimate Conclusion. Thus, whether Daubert's specific factors
are, or are not, reasonable measures of reliability in a particular case
is a matter that the law grants the trial Judge broad latitude to determine.
See id., at 143. The Eleventh Circuit erred insofar as it held to the contrary.
P. 13. |
| [23] | 2. Application of the foregoing standards demonstrates that the District
Court's decision not to admit Carlson's expert testimony was lawful. The
District Court did not question Carlson's qualifications, but excluded his
testimony because it initially doubted his methodology and then found it
unreliable after examining the transcript in some detail and considering
respondents' defense of it. The doubts that triggered the court's initial
inquiry were reasonable, as was the court's ultimate Conclusion that Carlson
could not reliably determine the cause of the failure of the tire in question.
The question was not the reliability of Carlson's methodology in general,
but rather whether he could reliably determine the cause of failure of the
particular tire at issue. That tire, Carlson conceded, had traveled far
enough so that some of the tread had been worn bald, it should have been
taken out of service, it had been repaired (inadequately) for punctures,
and it bore some of the very marks that he said indicated, not a defect,
but abuse. Moreover, Carlson's own testimony cast considerable doubt upon
the reliability of both his theory about the need for at least two signs
of abuse and his proposition about the significance of visual inspection
in this case. Respondents stress that other tire failure experts, like Carlson,
rely on visual and tactile examinations of tires. But there is no indication
in the record that other experts in the industry use Carlson's particular
approach or that tire experts normally make the very fine distinctions necessary
to support his Conclusions, nor are there references to articles or papers
that validate his approach. Respondents' argument that the District Court
too rigidly applied Daubert might have had some validity with respect to
the court's initial opinion, but fails because the court, on reconsideration,
recognized that the relevant reliability inquiry should be "flexible,"
and ultimately based its decision upon Carlson's failure to satisfy either
Daubert's factors or any other set of reasonable reliability criteria. Pp.
13-19. |
| [24] | 131 F. 3d 1433, reversed. |
| [25] | Breyer, J., delivered the opinion of the Court, in which Rehnquist, C.
J., and O'Connor, Scalia, Kennedy, Souter, Thomas, and Ginsburg, JJ., joined,
and in which Stevens, J., joined as to Parts I and II. Scalia, J., filed
a Concurring opinion, in which O'Connor and Thomas, JJ., joined. Stevens,
J., filed an opinion Concurring in part and Dissenting in part. |
| [26] | Court Below: 131 F.3d 1433 |
| [27] | The opinion of the court was delivered by: Justice Breyer |
| [28] | Opinion of the Court |
| [29] | KUMHO TIRE CO. v. CARMICHAEL |
| [30] | 526 U. S. ____ (1999) |
| [31] | On Writ Of Certiorari To The United States Court Of Appeals For The Eleventh
Circuit |
| [32] | In Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U. S. 579 (1993),
this Court focused upon the admissibility of scientific expert testimony.
It pointed out that such testimony is admissible only if it is both relevant
and reliable. And it held that the Federal Rules of Evidence "assign
to the trial Judge the task of ensuring that an expert's testimony both
rests on a reliable foundation and is relevant to the task at hand."
Id., at 597. The Court also discussed certain more specific factors, such
as testing, peer review, error rates, and "acceptability" in the
relevant scientific community, some or all of which might prove helpful
in determining the reliability of a particular scientific "theory or
technique." Id., at 593-594. |
| [33] | This case requires us to decide how Daubert applies to the testimony of
engineers and other experts who are not scientists. We conclude that Daubert's
general holding -- setting forth the trial Judge's general "gatekeeping"
obligation -- applies not only to testimony based on "scientific"
knowledge, but also to testimony based on "technical" and "other
specialized" knowledge. See Fed. Rule Evid. 702. We also conclude that
a trial court may consider one or more of the more specific factors that
Daubert mentioned when doing so will help determine that testimony's reliability.
But, as the Court stated in Daubert, the test of reliability is "flexible,"
and Daubert's list of specific factors neither necessarily nor exclusively
applies to all experts or in every case. Rather, the law grants a district
court the same broad latitude when it decides how to determine reliability
as it enjoys in respect to its ultimate reliability determination. See General
Electric Co. v. Joiner, 522 U. S. 136, 143 (1997) (courts of appeals are
to apply "abuse of discretion" standard when reviewing district
court's reliability determination). Applying these standards, we determine
that the District Court's decision in this case -- not to admit certain
expert testimony -- was within its discretion and therefore lawful. |
| [34] | I. |
| [35] | On July 6, 1993, the right rear tire of a minivan driven by Patrick Carmichael
blew out. In the accident that followed, one of the passengers died, and
others were severely injured. In October 1993, the Carmichaels brought this
diversity suit against the tire's maker and its distributor, whom we refer
to collectively as Kumho Tire, claiming that the tire was defective. The
plaintiffs rested their case in significant part upon deposition testimony
provided by an expert in tire failure analysis, Dennis Carlson, Jr., who
intended to testify in support of their Conclusion. |
| [36] | Carlson's depositions relied upon certain features of tire technology
that are not in dispute. A steel-belted radial tire like the Carmichaels'
is made up of a "carcass" containing many layers of flexible cords,
called "plies," along which (between the cords and the outer tread)
are laid steel strips called "belts." Steel wire loops, called
"beads," hold the cords together at the plies' bottom edges. An
outer layer, called the "tread," encases the carcass, and the
entire tire is bound together in rubber, through the application of heat
and various chemicals. See generally, e.g., J. Dixon, Tires, Suspension
and Handling 68-72 (2d ed. 1996). The bead of the tire sits upon a "bead
seat," which is part of the wheel assembly. That assembly contains
a "rim flange," which extends over the bead and rests against
the side of the tire. See M. Mavrigian, Performance Wheels & Tires 81,
83 (1998) (illustrations). |
| [37] | [Graphic omitted; see printed opinion.] |
| [38] | A. Markovich, How To Buy and Care For Tires 4 (1994). |
| [39] | Carlson's testimony also accepted certain background facts about the tire
in question. He assumed that before the blowout the tire had traveled far. |
| [40] | (The tire was made in 1988 and had been installed some time before the
Carmichaels bought the used minivan in March 1993; the Carmichaels had driven
the van approximately 7,000 additional miles in the two months they had
owned it.) Carlson noted that the tire's tread depth, which was 11/32 of
an inch when new, App. 242, had been worn down to depths that ranged from
3/32 of an inch along some parts of the tire, to nothing at all along others.
Id., at 287. He conceded that the tire tread had at least two punctures
which had been inadequately repaired. Id., at 258-261, 322. |
| [41] | Despite the tire's age and history, Carlson concluded that a defect in
its manufacture or design caused the blow-out. He rested this Conclusion
in part upon three premises which, for present purposes, we must assume
are not in dispute: First, a tire's carcass should stay bound to the inner
side of the tread for a significant period of time after its tread depth
has worn away. Id., at 208-209. Second, the tread of the tire at issue had
separated from its inner steel-belted carcass prior to the accident. Id.,
at 336. Third, this "separation" caused the blowout. Ibid. |
| [42] | Carlson's Conclusion that a defect caused the separation, however, rested
upon certain other propositions, several of which the defendants strongly
dispute. First, Carlson said that if a separation is not caused by a certain
kind of tire misuse called "overdeflection" (which consists of
underinflating the tire or causing it to carry too much weight, thereby
generating heat that can undo the chemical tread/carcass bond), then, ordinarily,
its cause is a tire defect. Id., at 193-195, 277-278. Second, he said that
if a tire has been subject to sufficient overdeflection to cause a separation,
it should reveal certain physical symptoms. These symptoms include (a) tread
wear on the tire's shoulder that is greater than the tread wear along the
tire's center, id., at 211; (b) signs of a "bead groove," where
the beads have been pushed too hard against the bead seat on the inside
of the tire's rim, id., at 196-197; (c) sidewalls of the tire with physical
signs of deterioration, such as discoloration, id., at 212; and/or (d) marks
on the tire's rim flange, id., at 219-220. Third, Carlson said that where
he does not find at least two of the four physical signs just mentioned
(and presumably where there is no reason to suspect a less common cause
of separation), he concludes that a manufacturing or design defect caused
the separation. Id., at 223-224. |
| [43] | Carlson added that he had inspected the tire in question. He conceded
that the tire to a limited degree showed greater wear on the shoulder than
in the center, some signs of "bead groove," some discoloration,
a few marks on the rim flange, and inadequately filled puncture holes (which
can also cause heat that might lead to separation). Id., at 256-257, 258-261,
277, 303-304, 308. But, in each instance, he testified that the symptoms
were not significant, and he explained why he believed that they did not
reveal overdeflection. For example, the extra shoulder wear, he said, appeared
primarily on one shoulder, whereas an overdeflected tire would reveal equally
abnormal wear on both shoulders. Id., at 277. Carlson concluded that the
tire did not bear at least two of the four overdeflection symptoms, nor
was there any less obvious cause of separation; and since neither overdeflection
nor the punctures caused the blowout, a defect must have done so. |
| [44] | Kumho Tire moved the District Court to exclude Carlson's testimony on
the ground that his methodology failed Rule 702's reliability requirement.
The court agreed with Kumho that it should act as a Daubert-type reliability
"gatekeeper," even though one might consider Carlson's testimony
as "technical," rather than "scientific." See Carmichael
v. Samyang Tires, Inc., 923 F. Supp. 1514, 1521-1522 (SD Ala. 1996). The
court then examined Carlson's methodology in light of the reliability-related
factors that Daubert mentioned, such as a theory's testability, whether
it "has been a subject of peer review or publication," the "known
or potential rate of error," and the "degree of acceptance ...
within the relevant scientific community." 923 F. Supp., at 1520 (citing
Daubert, 509 U. S., at 592-594). The District Court found that all those
factors argued against the reliability of Carlson's methods, and it granted
the motion to exclude the testimony (as well as the defendants' accompanying
motion for summary judgment). |
| [45] | The plaintiffs, arguing that the court's application of the Daubert factors
was too "inflexible," asked for reconsideration. And the Court
granted that motion. Carmichael v. Samyang Tires, Inc., Civ. Action No.
93-0860-CB-S (SD Ala., June 5, 1996), App. to Pet. for Cert. 1c. After reconsidering
the matter, the court agreed with the plaintiffs that Daubert should be
applied flexibly, that its four factors were simply illustrative, and that
other factors could argue in favor of admissibility. It conceded that there
may be widespread acceptance of a "visual-inspection method" for
some relevant purposes. But the court found insufficient indications of
the reliability of |
| [46] | "the component of Carlson's tire failure analysis which most concerned
the Court, namely, the methodology employed by the expert in analyzing the
data obtained in the visual inspection, and the scientific basis, if any,
for such an analysis." Id., at 6c. |
| [47] | It consequently affirmed its earlier order declaring Carlson's testimony
inadmissible and granting the defendants' motion for summary judgment. |
| [48] | The Eleventh Circuit reversed. See Carmichael v. Samyang Tire, Inc., 131
F. 3d 1433 (1997). It "review[ed] ... de novo" the "district
court's legal decision to apply Daubert." Id., at 1435. It noted that
"the Supreme Court in Daubert explicitly limited its holding to cover
only the `scientific context,' " adding that "a Daubert analysis"
applies only where an expert relies "on the application of scientific
principles," rather than "on skill- or experience-based observation."
Id., at 1435-1436. It concluded that Carlson's testimony, which it viewed
as relying on experience, "falls outside the scope of Daubert,"
that "the district court erred as a matter of law by applying Daubert
in this case," and that the case must be remanded for further (non-Daubert-type)
consideration under Rule 702. Id., at 1436. |
| [49] | Kumho Tire petitioned for certiorari, asking us to determine whether a
trial court "may" consider Daubert's specific "factors"
when determining the "admissibility of an engineering expert's testimony."
Pet. for Cert. i. We granted certiorari in light of uncertainty among the
lower courts about whether, or how, Daubert applies to expert testimony
that might be characterized as based not upon "scientific" knowledge,
but rather upon "technical" or "other specialized" knowledge.
Fed. Rule Evid. 702; compare, e.g., Watkins v. Telsmith, Inc., 121 F. 3d
984, 990-991 (CA5 1997), with, e.g., Compton v. Subaru of America, Inc.,
82 F. 3d 1513, 1518-1519 (CA10), cert. denied, 519 U. S. 1042 (1996). |
| [50] | II. |
| [51] | A. |
| [52] | In Daubert, this Court held that Federal Rule of Evidence 702 imposes
a special obligation upon a trial Judge to "ensure that any and all
scientific testimony ... is not only relevant, but reliable." 509 U.
S., at 589. The initial question before us is whether this basic gatekeeping
obligation applies only to "scientific" testimony or to all expert
testimony. We, like the parties, believe that it applies to all expert testimony.
See Brief for Petitioners 19; Brief for Respondents 17. |
| [53] | For one thing, Rule 702 itself says: |
| [54] | "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." |
| [55] | This language makes no relevant distinction between "scientific"
knowledge and "technical" or "other specialized" knowledge.
It makes clear that any such knowledge might become the subject of expert
testimony. In Daubert, the Court specified that it is the Rule's word "knowledge,"
not the words (like "scientific") that modify that word, that
"establishes a standard of evidentiary reliability." 509 U. S.,
at 589-590. Hence, as a matter of language, the Rule applies its reliability
standard to all "scientific," "technical," or "other
specialized" matters within its scope. We concede that the Court in
Daubert referred only to "scientific" knowledge. But as the Court
there said, it referred to "scientific" testimony "because
that [wa]s the nature of the expertise" at issue. Id., at 590, n. 8. |
| [56] | Neither is the evidentiary rationale that underlay the Court's basic Daubert
"gatekeeping" determination limited to "scientific"
knowledge. Daubert pointed out that Federal Rules 702 and 703 grant expert
witnesses testimonial latitude unavailable to other witnesses on the "assumption
that the expert's opinion will have a reliable basis in the knowledge and
experience of his discipline." Id., at 592 (pointing out that experts
may testify to opinions, including those that are not based on firsthand
knowledge or observation). The Rules grant that latitude to all experts,
not just to "scientific" ones. |
| [57] | Finally, it would prove difficult, if not impossible, for Judges to administer
evidentiary rules under which a gatekeeping obligation depended upon a distinction
between "scientific" knowledge and "technical" or "other
specialized" knowledge. There is no clear line that divides the one
from the others. Disciplines such as engineering rest upon scientific knowledge.
Pure scientific theory itself may depend for its development upon observation
and properly engineered machinery. And conceptual efforts to distinguish
the two are unlikely to produce clear legal lines capable of application
in particular cases. Cf. Brief for National Academy of Engineering as Amicus
Curiae 9 (scientist seeks to understand nature while the engineer seeks
nature's modification); Brief for Rubber Manufacturers Association as Amicus
Curiae 14-16 (engineering, as an "applied science," relies on
"scientific reasoning and methodology"); Brief for John Allen
et al. as Amici Curiae 6 (engineering relies upon "scientific knowledge
and methods"). |
| [58] | Neither is there a convincing need to make such distinctions. Experts
of all kinds tie observations to Conclusions through the use of what Judge
Learned Hand called "general truths derived from ... specialized experience."
Hand, Historical and Practical Considerations Regarding Expert Testimony,
15 Harv. L. Rev. 40, 54 (1901). And whether the specific expert testimony
focuses upon specialized observations, the specialized translation of those
observations into theory, a specialized theory itself, or the application
of such a theory in a particular case, the expert's testimony often will
rest "upon an experience confessedly foreign in kind to [the jury's]
own." Ibid. The trial Judge's effort to assure that the specialized
testimony is reliable and relevant can help the jury evaluate that foreign
experience, whether the testimony reflects scientific, technical, or other
specialized knowledge. |
| [59] | We conclude that Daubert's general principles apply to the expert matters
described in Rule 702. The Rule, in respect to all such matters, "establishes
a standard of evidentiary reliability." 509 U. S., at 590. It "requires
a valid ... connection to the pertinent inquiry as a precondition to admissibility."
Id., at 592. And where such testimony's factual basis, data, principles,
methods, or their application are called sufficiently into question, see
Part III, infra, the trial Judge must determine whether the testimony has
"a reliable basis in the knowledge and experience of [the relevant]
discipline." 509 U. S., at 592. |
| [60] | B. |
| [61] | The petitioners ask more specifically whether a trial Judge determining
the "admissibility of an engineering expert's testimony" may consider
several more specific factors that Daubert said might "bear on"
a Judge's gate-keeping determination. These factors include: |
| [62] | "-- Whether a "theory or technique ... can be (and has been)
tested"; |
| [63] | "-- Whether it "has been subjected to peer review and publication"; |
| [64] | "-- Whether, in respect to a particular technique, there is a high
"known or potential rate of error" and whether there are "standards
controlling the technique's operation"; and |
| [65] | "-- Whether the theory or technique enjoys "general acceptance"
within a "relevant scientific community." 509 U. S., at 592-594. |
| [66] | Emphasizing the word "may" in the question, we answer that question
yes. |
| [67] | Engineering testimony rests upon scientific foundations, the reliability
of which will be at issue in some cases. See, e.g., Brief for Stephen Bobo
et al. as Amici Curiae 23 (stressing the scientific bases of engineering
disciplines). In other cases, the relevant reliability concerns may focus
upon personal knowledge or experience. As the Solicitor General points out,
there are many different kinds of experts, and many different kinds of expertise.
See Brief for United States as Amicus Curiae 18-19, and n. 5 (citing cases
involving experts in drug terms, handwriting analysis, criminal modus operandi,
land valuation, agricultural practices, railroad procedures, attorney's
fee valuation, and others). Our emphasis on the word "may" thus
reflects Daubert's description of the Rule 702 inquiry as "a flexible
one." 509 U. S., at 594. Daubert makes clear that the factors it mentions
do not constitute a "definitive checklist or test." Id., at 593.
And Daubert adds that the gatekeeping inquiry must be " `tied to the
facts' " of a particular "case." Id., at 591 (quoting United
States v. Downing, 753 F. 2d 1224, 1242 (CA3 1985)). We agree with the Solicitor
General that "[t]he 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 testimony."
Brief for United States as Amicus Curiae 19. The Conclusion, in our view,
is that we can neither rule out, nor rule in, for all cases and for all
time the applicability of the factors mentioned in Daubert, nor can we now
do so for subsets of cases categorized by category of expert or by kind
of evidence. Too much depends upon the particular circumstances of the particular
case at issue. |
| [68] | Daubert itself is not to the contrary. It made clear that its list of
factors was meant to be helpful, not definitive. Indeed, those factors do
not all necessarily apply even in every instance in which the reliability
of scientific testimony is challenged. It might not be surprising in a particular
case, for example, that a claim made by a scientific witness has never been
the subject of peer review, for the particular application at issue may
never previously have interested any scientist. Nor, on the other hand,
does the presence of Daubert's general acceptance factor help show that
an expert's testimony is reliable where the discipline itself lacks reliability,
as, for example, do theories grounded in any so-called generally accepted
principles of astrology or necromancy. |
| [69] | At the same time, and contrary to the Court of Appeals' view, some of
Daubert's questions can help to evaluate the reliability even of experience-based
testimony. In certain cases, it will be appropriate for the trial Judge
to ask, for example, how often an engineering expert's experience-based
methodology has produced erroneous results, or whether such a method is
generally accepted in the relevant engineering community. Likewise, it will
at times be useful to ask even of a witness whose expertise is based purely
on experience, say, a perfume tester able to distinguish among 140 odors
at a sniff, whether his preparation is of a kind that others in the field
would recognize as acceptable. |
| [70] | We must therefore disagree with the Eleventh Circuit's holding that a
trial Judge may ask questions of the sort Daubert mentioned only where an
expert "relies on the application of scientific principles," but
not where an expert relies "on skill- or experience-based observation."
131 F. 3d, at 1435. We do not believe that Rule 702 creates a schematism
that segregates expertise by type while mapping certain kinds of questions
to certain kinds of experts. Life and the legal cases that it generates
are too complex to warrant so definitive a match. |
| [71] | To say this is not to deny the importance of Daubert's gatekeeping requirement.
The objective of that requirement is to ensure the reliability and relevancy
of expert testimony. It is to make certain that an expert, whether basing
testimony upon professional studies or personal experience, employs in the
courtroom the same level of intellectual rigor that characterizes the practice
of an expert in the relevant field. Nor do we deny that, as stated in Daubert,
the particular questions that it mentioned will often be appropriate for
use in determining the reliability of challenged expert testimony. Rather,
we conclude that the trial Judge must have considerable leeway in deciding
in a particular case how to go about determining whether particular expert
testimony is reliable. That is to say, a trial court should consider the
specific factors identified in Daubert where they are reasonable measures
of the reliability of expert testimony. |
| [72] | C. |
| [73] | The trial court must have the same kind of latitude in deciding how to
test an expert's reliability, and to decide whether or when special briefing
or other proceedings are needed to investigate reliability, as it enjoys
when it decides whether that expert's relevant testimony is reliable. Our
opinion in Joiner makes clear that a court of appeals is to apply an abuse-of-discretion
standard when it "review[s] a trial court's decision to admit or exclude
expert testimony." 522 U. S., at 138-139. That standard applies as
much to the trial court's decisions about how to determine reliability as
to its ultimate Conclusion. Otherwise, the trial Judge would lack the discretionary
authority needed both to avoid unnecessary "reliability" proceedings
in ordinary cases where the reliability of an expert's methods is properly
taken for granted, and to require appropriate proceedings in the less usual
or more complex cases where cause for questioning the expert's reliability
arises. Indeed, the Rules seek to avoid "unjustifiable expense and
delay" as part of their search for "truth" and the "jus[t]
determin[ation]" of proceedings. Fed. Rule Evid. 102. Thus, whether
Daubert's specific factors are, or are not, reasonable measures of reliability
in a particular case is a matter that the law grants the trial Judge broad
latitude to determine. See Joiner, supra, at 143. And the Eleventh Circuit
erred insofar as it held to the contrary. |
| [74] | III. |
| [75] | We further explain the way in which a trial Judge "may" consider
Daubert's factors by applying these considerations to the case at hand,
a matter that has been briefed exhaustively by the parties and their 19
amici. The District Court did not doubt Carlson's qualifications, which
included a masters degree in mechanical engineering, 10 years' work at Michelin
America, Inc., and testimony as a tire failure consultant in other tort
cases. Rather, it excluded the testimony because, despite those qualifications,
it initially doubted, and then found unreliable, "the methodology employed
by the expert in analyzing the data obtained in the visual inspection, and
the scientific basis, if any, for such an analysis." Civ. Action No.
93-0860-CB-S (SD Ala., June 5, 1996), App. to Pet. for Cert. 6c. After examining
the transcript in "some detail," 923 F. Supp., at 1518-519, n.
4, and after considering respondents' defense of Carlson's methodology,
the District Court determined that Carlson's testimony was not reliable.
It fell outside the range where experts might reasonably differ, and where
the jury must decide among the conflicting views of different experts, even
though the evidence is "shaky." Daubert, 509 U. S., at 596. In
our view, the doubts that triggered the District Court's initial inquiry
here were reasonable, as was the court's ultimate Conclusion. For one thing,
and contrary to respondents' suggestion, the specific issue before the court
was not the reasonableness in general of a tire expert's use of a visual
and tactile inspection to determine whether overdeflection had caused the
tire's tread to separate from its steel-belted carcass. Rather, it was the
reasonableness of using such an approach, along with Carlson's particular
method of analyzing the data thereby obtained, to draw a Conclusion regarding
the particular matter to which the expert testimony was directly relevant.
That matter concerned the likelihood that a defect in the tire at issue
caused its tread to separate from its carcass. The tire in question, the
expert conceded, had traveled far enough so that some of the tread had been
worn bald; it should have been taken out of service; it had been repaired
(inadequately) for punctures; and it bore some of the very marks that the
expert said indicated, not a defect, but abuse through overdeflection. See
supra, at 3-5; App. 293-294. The relevant issue was whether the expert could
reliably determine the cause of this tire's separation. Nor was the basis
for Carlson's Conclusion simply the general theory that, in the absence
of evidence of abuse, a defect will normally have caused a tire's separation.
Rather, the expert employed a more specific theory to establish the existence
(or absence) of such abuse. Carlson testified precisely that in the absence
of at least two of four signs of abuse (proportionately greater tread wear
on the shoulder; signs of grooves caused by the beads; discolored sidewalls;
marks on the rim flange) he concludes that a defect caused the separation.
And his analysis depended upon acceptance of a further implicit proposition,
namely, that his visual and tactile inspection could determine that the
tire before him had not been abused despite some evidence of the presence
of the very signs for which he looked (and two punctures). |
| [76] | For another thing, the transcripts of Carlson's depositions support both
the trial court's initial uncertainty and its final Conclusion. Those transcripts
cast considerable doubt upon the reliability of both the explicit theory
(about the need for two signs of abuse) and the implicit proposition (about
the significance of visual inspection in this case). Among other things,
the expert could not say whether the tire had traveled more than 10, or
20, or 30, or 40, or 50 thousand miles, adding that 6,000 miles was "about
how far" he could "say with any certainty." Id., at 265.
The court could reasonably have wondered about the reliability of a method
of visual and tactile inspection sufficiently precise to ascertain with
some certainty the abuse-related significance of minute shoulder/center
relative tread wear differences, but insufficiently precise to tell "with
any certainty" from the tread wear whether a tire had traveled less
than 10,000 or more than 50,000 miles. And these concerns might have been
augmented by Carlson's repeated reliance on the "subjective[ness]"
of his mode of analysis in response to questions seeking specific information
regarding how he could differentiate between a tire that actually had been
overdeflected and a tire that merely looked as though it had been. Id.,
at 222, 224-225, 285-286. They would have been further augmented by the
fact that Carlson said he had inspected the tire itself for the first time
the morning of his first deposition, and then only for a few hours. (His
initial Conclusions were based on photographs.) Id., at 180. |
| [77] | Moreover, prior to his first deposition, Carlson had issued a signed report
in which he concluded that the tire had "not been ... overloaded or
underinflated," not because of the absence of "two of four"
signs of abuse, but simply because "the rim flange impressions . .
. were normal." Id., at 335-336. That report also said that the "tread
depth remaining was 3/32 inch," id., at 336, though the opposing expert's
(apparently undisputed) measurements indicate that the tread depth taken
at various positions around the tire actually ranged from .5/32 of an inch
to 4/32 of an inch, with the tire apparently showing greater wear along
both shoulders than along the center, id., at 432-433. |
| [78] | Further, in respect to one sign of abuse, bead grooving, the expert seemed
to deny the sufficiency of his own simple visual-inspection methodology.
He testified that most tires have some bead groove pattern, that where there
is reason to suspect an abnormal bead groove he would ideally "look
at a lot of [similar] tires" to know the grooving's significance, and
that he had not looked at many tires similar to the one at issue. Id., at
212-213, 214, 217. |
| [79] | Finally, the court, after looking for a defense of Carlson's methodology
as applied in these circumstances, found no convincing defense. Rather,
it found (1) that "none" of the Daubert factors, including that
of "general acceptance" in the relevant expert community, indicated
that Carlson's testimony was reliable, 923 F. Supp., at 1521; (2) that its
own analysis "revealed no countervailing factors operating in favor
of admissibility which could outweigh those identified in Daubert,"
App. to Pet. for Cert. 4c; and (3) that the "parties identified no
such factors in their briefs," ibid. For these three reasons taken
together, it concluded that Carlson's testimony was unreliable. |
| [80] | Respondents now argue to us, as they did to the District Court, that a
method of tire failure analysis that employs a visual/tactile inspection
is a reliable method, and they point both to its use by other experts and
to Carlson's long experience working for Michelin as sufficient indication
that that is so. But no one denies that an expert might draw a Conclusion
from a set of observations based on extensive and specialized experience.
Nor does anyone deny that, as a general matter, tire abuse may often be
identified by qualified experts through visual or tactile inspection of
the tire. See Affidavit of H. R. Baumgardner 1-2, cited in Brief for National
Academy of Forensic Engineers as Amici Curiae 16 (Tire engineers rely on
visual examination and process of elimination to analyze experimental test
tires). As we said before, supra, at 14, the question before the trial court
was specific, not general. The trial court had to decide whether this particular
expert had sufficient specialized knowledge to assist the jurors "in
deciding the particular issues in the case." 4 J. McLaughlin, Weinstein's
Federal Evidence ¶ ;702.05[1], p. 702-33 (2d ed. 1998); see also Advisory
Committee's Note on Proposed Fed. Rule Evid. 702, Preliminary Draft of Proposed
Amendments to the Federal Rules of Civil Procedure and Evidence: Request
for Comment 126 (1998) (stressing that district courts must "scrutinize"
whether the "principles and methods" employed by an expert "have
been properly applied to the facts of the case"). |
| [81] | The particular issue in this case concerned the use of Carlson's two-factor
test and his related use of visual/tactile inspection to draw Conclusions
on the basis of what seemed small observational differences. We have found
no indication in the record that other experts in the industry use Carlson's
two-factor test or that tire experts such as Carlson normally make the very
fine distinctions about, say, the symmetry of comparatively greater shoulder
tread wear that were necessary, on Carlson's own theory, to support his
Conclusions. Nor, despite the prevalence of tire testing, does anyone refer
to any articles or papers that validate Carlson's approach. Compare Bobo,
Tire Flaws and Separations, in Mechanics of Pneumatic Tires 636-637 (S.
Clark ed. 1981); C. Schnuth et al., Compression Grooving and Rim Flange
Abrasion as Indicators of Over-Deflected Operating Conditions in Tires,
presented to Rubber Division of the American Chemical Society, Oct. 21-24,
1997; J. Walter & R. Kiminecz, Bead Contact Pressure Measurements at
the Tire-Rim Interface, presented to Society of Automotive Engineers, Feb.
24-28, 1975. Indeed, no one has argued that Carlson himself, were he still
working for Michelin, would have concluded in a report to his employer that
a similar tire was similarly defective on grounds identical to those upon
which he rested his Conclusion here. Of course, Carlson himself claimed
that his method was accurate, but, as we pointed out in Joiner, "nothing
in either Daubert or the Federal Rules of Evidence requires a district court
to admit opinion evidence that is connected to existing data only by the
ipse dixit of the expert." 522 U. S., at 146. |
| [82] | Respondents additionally argue that the District Court too rigidly applied
Daubert's criteria. They read its opinion to hold that a failure to satisfy
any one of those criteria automatically renders expert testimony inadmissible.
The District Court's initial opinion might have been vulnerable to a form
of this argument. There, the court, after rejecting respondents' claim that
Carlson's testimony was "exempted from Daubert-style scrutiny"
because it was "technical analysis" rather than "scientific
evidence," simply added that "none of the four admissibility criteria
outlined by the Daubert court are satisfied." 923 F. Supp., at 1522.
Subsequently, however, the court granted respondents' motion for reconsideration.
It then explicitly recognized that the relevant reliability inquiry "should
be `flexible,' " that its " `overarching subject [should be] ...
validity' and reliability," and that "Daubert was intended neither
to be exhaustive nor to apply in every case." App. to Pet. for Cert.
4c (quoting Daubert, 509 U. S., at 594-595). And the court ultimately based
its decision upon Carlson's failure to satisfy either Daubert's factors
or any other set of reasonable reliability criteria. In light of the record
as developed by the parties, that Conclusion was within the District Court's
lawful discretion. |
| [83] | In sum, Rule 702 grants the district Judge the discretionary authority,
reviewable for its abuse, to determine reliability in light of the particular
facts and circumstances of the particular case. The District Court did not
abuse its discretionary authority in this case. Hence, the judgment of the
Court of Appeals is |
| [84] | Reversed. |
| [85] | Scalia, J., Concurring |
| [86] | KUMHO TIRE CO. v. CARMICHAEL |
| [87] | ____ U. S. ____ (1999) |
| [88] | SUPREME COURT OF THE UNITED STATES |
| [89] | No. 97-1709 |
| [90] | KUMHO TIRE COMPANY, LTD., et al., PETITIONERS v. PATRICK CARMICHAEL, etc.,
et al. |
| [91] | on writ of certiorari to the united states court of appeals for the eleventh
circuit |
| [92] | [March 23, 1999] |
| [93] | Justice Scalia, with whom Justice O'Connor and Justice Thomas join, Concurring. |
| [94] | I join the opinion of the Court, which makes clear that the discretion
it endorses -- trial-court discretion in choosing the manner of testing
expert reliability -- is not discretion to abandon the gatekeeping function.
I think it worth adding that it is not discretion to perform the function
inadequately. Rather, it is discretion to choose among reasonable means
of excluding expertise that is fausse and science that is junky. Though,
as the Court makes clear today, the Daubert factors are not holy writ, in
a particular case the failure to apply one or another of them may be unreasonable,
and hence an abuse of discretion. |
| [95] | Stevens, J., Dissenting |
| [96] | KUMHO TIRE CO. v. CARMICHAEL |
| [97] | ____ U. S. ____ (1999) |
| [98] | SUPREME COURT OF THE UNITED STATES |
| [99] | No. 97-1709 |
| [100] | KUMHO TIRE COMPANY, LTD., et al., PETITIONERS v. PATRICK CARMICHAEL, etc.,
et al. |
| [101] | on writ of certiorari to the united states court of appeals for the eleventh
circuit |
| [102] | [March 23, 1999] |
| [103] | Justice Stevens, Concurring in part and Dissenting in part. |
| [104] | The only question that we granted certiorari to decide is whether a trial
Judge "[m]ay . . . consider the four factors set out by this Court
in Daubert v. Merrill Dow Pharmaceuticals, Inc., 509 U. S. 579 (1993), in
a Rule 702 analysis of admissibility of an engineering expert's testimony."
Pet. for Cert. i. That question is fully and correctly answered in Parts
I and II of the Court's opinion, which I join. |
| [105] | Part III answers the quite different question whether the trial Judge
abused his discretion when he excluded the testimony of Dennis Carlson.
Because a proper answer to that question requires a study of the record
that can be performed more efficiently by the Court of Appeals than by the
nine Members of this Court, I would remand the case to the Eleventh Circuit
to perform that task. There are, of course, exceptions to most rules, but
I firmly believe that it is neither fair to litigants nor good practice
for this Court to reach out to decide questions not raised by the certiorari
petition. See General Electric Co. v. Joiner, 522 U. S. 136, 150-151 (1997)
(Stevens, J., Concurring in part and Dissenting in part). |
| [106] | Accordingly, while I do not feel qualified to disagree with the well-reasoned
factual analysis in Part III of the Court's opinion, I do not join that
Part, and I respectfully Dissent from the Court's Disposition of the case. |
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