526 U.S. 137 (1999)
On July 6, 1993, the right rear tire of a minivan driven by Patrick Carmichael blew out.1 In the accident that followed, one of the passengers died, and others were severely injured.2 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.3 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.4
Carlson's depositions relied upon features of tire technology, such as the carcass, plies, belts, beads, and tread, that are not in dispute.5 The tire was made in 1988 and had been installed some time before the Carmichaels bought the used minivan in March 1993.6 The Carmichaels had driven the van approximately 7,000 additional miles in the two months they had owned it.7 Carlson noted that the tire's tread depth, which was 11/32 of an inch when new, 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.8 He conceded that the tire tread had at least two punctures which had been inadequately repaired.9
Carlson concluded that a defect in its manufacture or design caused the blowout.10 He rested this conclusion in part upon three premises which, for present purposes, we must assume are not in dispute.11 Carlson's conclusion that a defect caused the separation, however, rested upon other propositions, several of which the defendants strongly dispute.12 Carlson added that he had inspected the tire in question.13
Kumho Tire moved the District Court to exclude Carlson's testimony on the ground that his methodology failed Rule 702's reliability requirement.14 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.15 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.16 The plaintiffs asked for reconsideration, and the court granted that motion.17 After reconsidering the matter, the court agreed with the plaintiffs that Daubert should be applied flexibly.18 It consequently affirmed its earlier order declaring Carlson's testimony inadmissible and granting the defendants' motion for summary judgment.19
The Eleventh Circuit reversed.20 It reviewed de novo the district court's legal decision to apply Daubert.21 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 702.22 Kumho Tire petitioned for certiorari, asking the Court to determine whether a trial court may consider Daubert's specific factors when determining the admissibility of an engineering expert's testimony.23 The Supreme Court 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.24
Whether Daubert's general holding setting forth the trial judge's gatekeeping obligation applies to testimony based on technical and other specialized knowledge?25
Federal Rule of Evidence 702 imposes upon the trial judge a special obligation to ensure that any and all expert testimony is not only relevant but reliable, establishing a standard of evidentiary reliability that applies without distinction to scientific, technical, or other specialized knowledge.26
Yes. The text of Rule 702 draws no distinction between categories of expert knowledge.27 The rationale for the gatekeeping function extends equally to all forms of expertise.28 The Rules grant testimonial latitude to experts on the assumption that their opinions rest on a reliable basis in the knowledge and experience of their discipline.29
In this case the Carmichaels offered the deposition testimony of Dennis Carlson, an expert in tire failure analysis whose conclusions rested on visual and tactile inspection of the tire's tread wear, bead grooves, sidewall discoloration, and rim flange marks.30 That testimony constituted technical and experience-based knowledge rather than pure scientific theory.31 The District Court therefore properly exercised its gatekeeping role by examining the reliability of Carlson's methodology even though the testimony was not scientific in nature.32
Daubert's gatekeeping obligation applies to all expert testimony, including testimony based on technical and other specialized knowledge.33
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Joined by O'connor And Thomas, Jj.
Justice Scalia joined the Court's opinion.34 He stressed that the discretion recognized in choosing the manner of testing expert reliability is not discretion to abandon the gatekeeping function.35 It is not discretion to perform the function inadequately.36
Rather, it is discretion to choose among reasonable means of excluding expertise that is false and science that is junky.37 Though 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.38
Whether a trial court may consider one or more of the specific factors that Daubert mentioned when determining the reliability of expert testimony?39
A trial court may consider the specific factors identified in Daubert, such as testability, peer review, known or potential rate of error, and general acceptance, when doing so will help determine the reliability of expert testimony, but the inquiry remains flexible and the factors need not be applied in every case or to every expert.40
Yes. Daubert described its list of factors as illustrative rather than definitive.41 The Court has made clear that the gatekeeping inquiry must be tied to the facts of the particular case and the nature of the expert's expertise.42
Here the District Court initially considered the Daubert factors and found each weighed against the reliability of Carlson's visual-inspection methodology.43 On reconsideration the court recognized that the factors are not exhaustive and that other reliability criteria could be considered.44 Yet it still concluded that Carlson's two-factor test and his application of visual and tactile inspection lacked sufficient indicia of reliability.45 That approach was consistent with the flexible, case-specific inquiry permitted by the Rules.
A trial court may consider one or more of the specific Daubert factors when determining the reliability of expert testimony.46
Whether the District Court's decision not to admit the expert testimony was within its discretion?47
Yes. The District Court did not doubt Carlson's qualifications but found that his methodology, including the specific theory requiring at least two signs of overdeflection and the implicit claim that visual inspection could reliably rule out abuse despite the presence of some of those signs, lacked sufficient reliability under any reasonable set of criteria.50
The transcripts revealed that Carlson could not state with certainty how many miles the tire had traveled.51 His initial report had relied on different reasoning than his later two-factor test.52 He had not examined comparable tires to calibrate his observations.53 The court also noted the absence of peer review, general acceptance, or other validating evidence for Carlson's particular approach.54 These facts supported the conclusion that the testimony fell outside the range where experts might reasonably differ.55 The District Court's exclusion of the evidence therefore constituted a lawful exercise of its discretion.56
The District Court's decision not to admit the expert testimony was within its discretion.57
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Justice Stevens joined Parts I and II of the opinion.58 He dissented from the disposition because he believed the question whether the trial judge abused his discretion in excluding Carlson's testimony was not fairly presented by the certiorari petition.59 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.60
He would have remanded the case to the Eleventh Circuit to perform that task.61 There are exceptions to most rules, but it is neither fair to litigants nor good practice for this Court to reach out to decide questions not raised by the certiorari petition.62