Kumho Tire Co. v. Carmichael

[*141] Justice Breyer delivered the opinion of the Court.

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.

This case requires us to decide how Daubert applies to the testimony of engineers and other experts who are not scientists. We conclude that Dauberfs 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 Dauberfs list of specific factors neither necessarily nor exclusively applies to all experts or in every case. [*142] 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.