The Case Against Abandoning the Search for Substantive Accuracy

23 Pages Posted: 12 Sep 2007  

Edward J. Imwinkelried

University of California, Davis - School of Law


(This paper will be the basis for the author's remarks at the 2008 meeting of the Evidence Section at the A.A.L.S. meeting. It will later be published in SETON HALL LAW REVIEW.)

Professor Christopher Slobogin's new book, PROVING THE UNPROVABLE (2007), is one of the most provocative Evidence texts released in recent 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 precludes the application of the normal expert testimony standards prescribed by Daubert and Kumho.

Instead, Professor Slobogin proposes generally accepted content validity as the standard for admissibility. His proposal is a step in the right direction. The proposal would at least ensure that the expert's opinion represents something more than the expert's personal ipse dixit. Moreover, his analysis is balanced. While he states that "scientifically verified evidence" is "usually" unavailable as a basis for expert testimony about past mental state, he adds the qualification that "[i]n those few instances when scientifically reliable information material to [the] issue [of past mental state] is available, the expert should rely on it."

My fear, though, is that some may not read PROVING THE UNPROVABLE closely enough and will lose sight of the important qualifications Professor Slobogin adds. The book is argued so forcefully that readers may instead focus on the broad language suggesting that the very nature of the topic precludes policing the substantive accuracy of the relevant expert testimony.

I have grave doubts about the wisdom of a general call to abandon the search for substantive accuracy in psychological and psychiatric testimony. The purpose of this short article is to explain the source of those doubts. The first part of this article is a descriptive survey of the state of the art of determining malingering by subjects of psychological and psychiatric interviews. The second part of the article is a critical evaluation of the state of that art. The third and final part of the articles inquires what light the state of the art of malingering detection sheds on the question of whether it is necessary to abandon the attempt to ensure the substantive accuracy of testimony by psychologists and psychiatrists about a person's prior mental state.

Suggested Citation

Imwinkelried, Edward J., The Case Against Abandoning the Search for Substantive Accuracy. Seton Hall Law Review, Forthcoming; UC Davis Legal Studies Research Paper No. 117. Available at SSRN:

Edward J. Imwinkelried (Contact Author)

University of California, Davis - School of Law ( email )

Martin Luther King, Jr. Hall
Davis, CA CA 95616-5201
United States

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