The Case Against Abandoning the Search for Substantive Accuracy

Professor Slobogin’s new book, Proving the Unprovable, is the most provocative evidence text that I have read in years. In the book, he argues in favor of a more relaxed standard for admitting psychologists’ and psychiatrists’ testimony about a person’s prior mental state. He contends that a person’s earlier mental state is essentially unprovable and that it is impossible to gauge the validity of such testimony in the sense of its substantive accuracy. He concludes that the nature of such testimony ordinarily precludes the application of the normal expert testimony standards prescribed by Daubert v. Merrell Dow Pharmaceuticals, Inc. and Kumho Tire Co. v. Carmichael. Instead, he proposes generally accepted content validity as the standard for admissibility. The proposal contemplates the creation of a database of cases in which psychiatrists’ or psychologists’ testimony about prior mental state was used. The database would include information such as the reports, testimony, and verdict in the case to identify the factors that the legal decisionmaker considered relevant. The database would be used to refine structured interview