Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993)
Daubert v. Merrell Dow Pharmaceuticals is the foundational case governing the admissibility of expert scientific testimony in federal courts.
Do the Federal Rules of Evidence, particularly Rule 702, displace the Frye "general acceptance" test for scientific expert testimony, and if so, what standard governs the admissibility of such evidence?
Under Federal Rule of Evidence 702, the trial judge must act as a gatekeeper to ensure that scientific expert testimony is both reliable and relevant. Reliability requires that the testimony constitute "scientific knowledge" grounded in the methods and procedures of science, not mere subjective belief or unsupported speculation. Relevant expert testimony must "fit" the case by assisting the trier of fact to understand the evidence or determine a fact in issue. In making this preliminary determination under Rule 104(a) (by a preponderance of the evidence), courts engage in a flexible, case-specific inquiry and may consider nonexclusive factors such as: (1) whether the theory or technique can be and has been tested; (2) whether it has been subjected to peer review and publication; (3) the known or potential rate of error and the existence and maintenance of standards; and (4) general acceptance within the relevant scientific community. The Frye test of general acceptance is not a necessary or sufficient condition for admissibility under the Federal Rules.
The Federal Rules of Evidence supersede Frye's "general acceptance" test. Rule 702 imposes a flexible, reliability-and-relevance gatekeeping role on trial judges for scientific expert testimony. The Ninth Circuit's application of Frye was error; the judgment was vacated and the case remanded for further proceedings under the proper standard.
Daubert is the cornerstone of modern expert evidence law. It replaced Frye's rigid general-acceptance test with a flexible, judge-centered reliability and relevance inquiry under Rule 702. The decision established that trial judges must screen expert testimony for methodological soundness and fit, leading to pretrial Daubert motions and hearings that can be outcome-determinative, especially in scientific causation cases. Daubert also launched the "Daubert trilogy": General Electric Co. v. Joiner (1997) (abuse-of-discretion appellate review and scrutiny of analytical gaps) and Kumho Tire Co. v. Carmichael (1999) (extending Daubert's gatekeeping to all expert testimony, not just "scientific"). Subsequent amendments to Rule 702 (notably in 2000 and 2023) codify and clarify the gatekeeping role and the proponent's burden. Many states have adopted Daubert or variants; others retain Frye. For law students, Daubert is essential for understanding the interplay between evidence law, scientific methodology, and civil procedure strategy.