13 March 2020

Questioning Forensic Psychology

Welcome back. Nearly two years ago, on another website, I described two problems confronting forensic science--the application of scientific principles and techniques to criminal justice (reposted here as Forensic Science Gap).

One problem is that forensic science is, well, short on science. The second problem was that the Trump administration had just terminated an Obama-era initiated commission established to research and make recommendations for improving forensic professionals and laboratories.

Forensic science can be short on science (graphic from www.knowablemagazine.org/article/society/2018/when-courtroom-science-goes-wrong-and-how-stats-can-fix-it).
I’ll pass on revisiting the second problem, but a recent study stirred thoughts about the first problem.

My earlier post addressed forensic methods, such as bite mark analysis, which evolved outside of traditional science before Supreme Court rulings led to the requirement that scientific evidence must be both reliable and relevant.

The recent thought-stirring study concerns forensic psychology, where psychological science or professional practice is applied to help resolve legal, contractual or administrative matters. It appears that forensic psychology is also short on science.

Forensic psychologist contribution in legal matters
(from Forensic Psychology Essentials webinar
Forensic Psychology Study
A team of researchers affiliated with Arizona State, Vanderbilt, California and Nebraska-Lincoln universities conducted a two-part investigation.

They first reviewed the scientific basis of 364 psychological assessment tools identified in 22 surveys of mental health practitioners as having been used or acceptable for use in forensic settings.

The second part of the investigation analyzed legal challenges to admitting evidence provided by these tools.

Psychological Assessment Tools
The 364 psychological assessment tools reviewed by the researchers included:
- aptitude, achievement, personality, psychological and diagnostic tests;
- measures designed for both adults and youth; and
- tools that can be used to address referral questions (e.g., competence or fitness to stand trial, violence or sexual offender risk assessment, mental state at time of offense, aid in sentencing, disability, child custody or protection, civil commitment, civil tort, guardianship, competency to consent to treatment, juvenile transfer to adult court, fitness for duty and capacity to waive Miranda rights).

Forensic psychological assessment testing
(photo from www.sacap.edu.za/blog/psychology/types-of-psychology/).
They could not find manuals for about a quarter of the tools and postulated that about 10% have no manual.

More significant, about 37% of the 364 tools lacked any authoritative reviews in recognized review sources (e.g., Mental Measurements Yearbook). Of the tools reviewed, only about 40% received generally favorable reviews. Reviews of 37% of the tools were mixed, and reviews of 23% were generally unfavorable. Some tools had apparently been published without scientific peer review or scientifically sound testing.

Court Acceptance of Psychological Assessment Tools
To focus the second part of the investigation, the researchers selected 30 of the 364 tools as exemplars. This subset of tools represented a wide range of legal issues and forensic referral questions as well as a variety of general acceptance and quality.

The researchers searched three example years, 2016, 2017 and 2018, and found 372 state and federal cases that had used one of the 30 tools. The tool’s admissibility or the admissibility of testimony relying on the tool was challenged in only 19 of the 372 cases, and only 6 challenges succeeded.

The admissibility challenges in the 19 cases involved 9 of the 30 psychological assessment tools. Of the 9 tools, 5 had favorable reviews, 2 had mixed reviews, and 2 lacked any review but were generally accepted.

Wrap Up
The study found that many of the assessment tools used by psychologists and admitted into legal contexts have weak or unknown scientific foundations. Attorneys rarely challenge the expert evidence, and judges tend not to subject psychological assessment evidence to the scrutiny required by the law.

In short, evidentiary challenges to psychological tools are rare, and challenges to scientifically suspect tools are even rarer or nonexistent. The researchers hope the study will help bring about change.

Thanks for stopping by.

Study of psychological assessments in legal contexts in Psychological Science in the Public Interest journal: journals.sagepub.com/stoken/default+domain/10.1177%2F1529100619888860+-+FREE/pdf
Articles on study on Assoc. for Psychological Science and EurekAlert! websites:

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