Expert Testimony in Psychology: Ramifications of Supreme Court Decision in Kumho Tire Co., Ltd. v. Carmichael

Abstract

A recent Supreme Court decision, Kumho Tire Co., Ltd. v. Carmichael (March 23, 1999), may have substantial impact on psychological expert testimony. Previous criteria for admissibility of scientific expert testimony now apply broadly to expert testimony, not just testimony narrowly grounded in scientific evidence. Judges will determine the relevance and reliability of all expert testimony, including that based on clinical experience or training. Admissible testimony will either satisfy the criteria established in Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) or meet similarly rigorous standards judged appropriate to the particular field involved. Because psychological testimony has varied in its evidentiary basis, sometimes relying on science and otherwise on clinical training or experience, court decisions will gradually determine the precedent for its admissibility. We also discuss long-term consequences for the credibility of psychological expert testimony and the relation between psychology and law.