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

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.

Misconceptions About Nonverbal Cues to Deception: A Covert Threat to the Justice System?

“…This is all the more worrisome considering that, even if they are mentioned in written judgments, the assessment of witness credibility is rarely reviewed by appellate courts because, amongst other thing, they cannot "see and hear" the witnesses as judges previously did (Timony, 2000;Denault, 2015). Therefore, judges receive very little feedback and, as a consequence, could read manuals, and attend seminars promoting unfounded, discredited and pseudoscientific claims, all in good faith, throughout their career, without ever being told that, in fact, what they learned is unproven and amounts to nothing more than "junk science" (DeMatteo et al, 2019;Neal et al, 2019).…”

Expert Evidence: The (Unfulfilled) Promise of Daubert

“…Given the rate at which expert testimony is being offered by psychologists (see Melton et al, 2018), examining whether the assessment methods used by psychologists satisfy the Daubert criteria has clear importance. Neal, Slobogin, Saks, Faigman, and Geisinger (2019) answered the call in their ambitious, rigorous, and timely study of the admissibility of psychological assessment tools. In their article, Neal et al (2019) report on the results of their two-part investigation of psychological assessment tools in legal contexts.…”

“…Neal, Slobogin, Saks, Faigman, and Geisinger (2019) answered the call in their ambitious, rigorous, and timely study of the admissibility of psychological assessment tools. In their article, Neal et al (2019) report on the results of their two-part investigation of psychological assessment tools in legal contexts. Using the results from 23 previous surveys of forensic mental health professionals, they first conducted a systematic review of the 364 psychological assessment tools that psychologists have reported using in legal contexts.…”

“…Specifically, they found that admissibility challenges occurred in approximately 5% of the cases they reviewed, and challenges were successful in approximately one third of those cases. Expert witnesses are considered experts by the courts because they have advanced knowledge that a lay person does not, so it is difficult for judges and attorneys-who often lack the necessary training to understand and challenge proffered expert testimony-to critically examine the expert's data, methods, and conclusions, which probably accounts for the low rates of evidentiary challenges found by Neal et al (2019). In Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993), the Supreme Court recognized the difficulty in evaluating expert evidence when it observed that such evidence "can be both powerful and quite misleading because of the difficulty in evaluating it" (p. 595).…”

“…Ensuring that forensic psychological practice is built on a solid empirical foundation encourages the continued use of psychologists in legal contexts, enhances the credibility of the field, and gives greater weight to psychological advocacy. Thus, researchers should continually critique the current state of forensic practice, as Neal et al (2019) did in their article. The troubling results they present raise an obvious concern that junk science is being admitted into court proceedings with some regularity.…”