Where the Rubber Meets the Road: Thinking About Expert Evidence as Expert Testimony

Abstract

Taking stock more than a decade after Daubert v. Merrell Dow Pharmaceuticals, this paper argues that legal scholars, including the author, have perhaps focused too much on the validity of expert evidence and not enough on the propriety of expert testimony. It argues that legal scholars who disagree about many aspects of expert evidence nonetheless agree that "fit" between the testimonial claim and the empirical support for that claim is a crucial issue. The paper then suggests that much of the recent controversies over forensic evidence may be attributed to what Professor Friedman has called "over-claiming," the exaggeration of the probative value of the evidence during expert testimony. The paper concludes by presenting some empirical data from a study of actual expert testimony about latent print analysis. The testimonial claims vary significantly from case to case, but fall into several broad categories. Although the testimonial claims are not always logical on their face, the paper argues that these testimonial claims make juries comfortable with conviction. The paper concludes by calling for more scholarly attention to expert evidence as expert testimony.

Keywords: Daubert, expert evidence, fingerprints, forensic science, expert testimony, science and technology studies