Evaluating the Reliability of Nonscientific Expert Testimony: A Partial Answer to the Questions Left Unresolved by Kumho Tire Co. v. Carmichael

For almost three-quarters of a century, the venerable standard announced in Frye v. United States governed the admissibility of scientific evidence. The Court of Appeals for the District of Columbia handed down the Frye decision in 1923. Under Frye, the proponent of testimony had to demonstrate that the expert\u27s testimony was based on a generally accepted theory or technique. However, in 1993--seventy years after the rendition of the Frye decision--another court sitting in Washington, the United States Supreme Court, overturned the standard. The Court did so in its now celebrated Daubert v. Merrell Dow Pharmaceuticals decision. In the interim between Frye and Daubert, Congress enacted the Federal Rules of Evidence. The statutory scheme includes Federal Rule of Evidence 702, reading: “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.” Although Daubert gave the lower courts extensive guidance on how to gauge the admissibility of scientific testimony, in a footnote the Court pointed out that it was not prescribing standards for the introduction of nonscientific expert testimony such as opinions by musicians or automotive mechanics. The Court stated: “Rule 702 also applies to ‘technical, or other specialized knowledge.’ Our discussion is limited to the scientific context because that is the nature of the expertise offered here.” That footnote left open the question of whether, and if so to what extent, Daubert applied to nonscientific expert testimony. That split of authority set the stage for the Supreme Court\u27s 1999 decision in Kumho Tire Co. v. Carmichael. Like Daubert, Kumho Tire is certain to generate a massive amount of commentary. If anything, Kumho Tire may spawn a larger body of commentary. The Daubert opinion at least gave the lower courts extensive guidance on the factors to utilize in assessing the admissibility of tendered scientific evidence. In contrast, the Kumho Tire Court adamantly refused to rule in or out specific factors in particular cases. Kumho Tire leaves so many unanswered questions that it invites commentators to attempt to fill the gaps in the opinion. In the aftermath of Daubert, many commentators attempted to deduce a grand vision of science underlying Justice Blackmun\u27s opinion. There may be similar, ambitious efforts to extract from Kumho Tire a metatheory of the reliability of expert testimony. This Article eschews that ambition. This Article has a far more limited objective. Its goal is to identify two specific factors which trial judges may find useful in many cases in which they face the task of ruling on the admissibility of nonscientific expert testimony