Psychological Assessments in Legal Contexts: Are Courts Keeping 'Junk Science' Out of the Courtroom?

20 Psychological Science in the Public Interest 134-164 (2020)

Vanderbilt Law Research Paper No. 20-28

UC Hastings Research Paper No. 383

32 Pages Posted: 17 Apr 2020 Last revised: 16 Jun 2020

See all articles by Tess M.S. Neal

Tess M.S. Neal

Arizona State University

Christopher Slobogin

Vanderbilt University - Law School

Michael J. Saks

Arizona State University (ASU) - Sandra Day O'Connor College of Law

David L. Faigman

University of California Hastings College of the Law

Kurt F. Geisinger

University of Nebraska at Lincoln

Date Written: March 23, 2020

Abstract

In this article, we report the results of a two-part investigation of psychological assessments by psychologists in legal contexts. The first part involves a systematic review of the 364 psychological assessment tools psychologists report having used in legal cases across 22 surveys of experienced forensic mental health practitioners, focusing on legal standards and scientific and psychometric theory. The second part is a legal analysis of admissibility challenges with regard to psychological assessments. Results from the first part reveal that, consistent with their roots in psychological science, nearly all of the assessment tools used by psychologists and offered as expert evidence in legal settings have been subjected to empirical testing (90%). However, we were able to clearly identify only about 67% as generally accepted in the field and only about 40% have generally favorable reviews of their psychometric and technical properties in authorities such as the Mental Measurements Yearbook. Furthermore, there is a weak relationship between general acceptance and favorability of tools’ psychometric properties. Results from the second part show that legal challenges to the admission of this evidence are infrequent: Legal challenges to the assessment evidence for any reason occurred in only 5.1% of cases in the sample (a little more than half of these involved challenges to validity). When challenges were raised, they succeeded only about a third of the time. Challenges to the most scientifically suspect tools are almost nonexistent. Attorneys rarely challenge psychological expert assessment evidence, and when they do, judges often fail to exercise the scrutiny required by law.

Keywords: psycholgoical tests, forensic evaluation, psychometric, Daubert, expert

Suggested Citation

Neal, Tess M.S. and Slobogin, Christopher and Saks, Michael J. and Faigman, David L. and Geisinger, Kurt F., Psychological Assessments in Legal Contexts: Are Courts Keeping 'Junk Science' Out of the Courtroom? (March 23, 2020). 20 Psychological Science in the Public Interest 134-164 (2020), Vanderbilt Law Research Paper No. 20-28, UC Hastings Research Paper No. 383, Available at SSRN: https://ssrn.com/abstract=3559823

Tess M.S. Neal (Contact Author)

Arizona State University ( email )

4701 West Thunderbird Rd.
Mailcode 3051
Glendale, AZ 85306
United States
602-543-5680 (Phone)

HOME PAGE: http://psych-law.lab.asu.edu/

Christopher Slobogin

Vanderbilt University - Law School ( email )

131 21st Avenue South
Nashville, TN 37203-1181
United States

Michael J. Saks

Arizona State University (ASU) - Sandra Day O'Connor College of Law ( email )

111 E. Taylor Street
MC-9520
Phoenix, AZ 85004
United States

David L. Faigman

University of California Hastings College of the Law ( email )

200 McAllister Street
San Francisco, CA 94102
United States

Kurt F. Geisinger

University of Nebraska at Lincoln

Lincoln, NE 68588
United States

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