Experts Screening Experts: Are Courts Effectively Gatekeeping Psychological Assessment Evidence?

The United States Supreme Court’s 1993 Daubert v. Merrell Dow Pharmaceuticals case established criteria for admitting scientific evidence in federal courts. It holds that scientific evidence must be valid, reliable, and relevant, and judges are required to be “gatekeepers” of evidence by screening out evidence that has not been empirically tested or vetted through the academic community. Yet, little is known about whether psychological assessment tools are subjected to scrutiny through the standards courts are supposed to apply. In three different studies, from the perspectives of judges, attorneys, and forensic mental health experts, the authors investigate whether psychological assessment evidence is being challenged. Information was collected on participants’ experiences with challenges to psychological assessments. Judges and lawyers completed a series of experimental case vignettes to assess their decision-making about legal admissibility of different qualities of psychological assessments. It was hypothesized they would not distinguish between low- and high-quality psychological assessments in admissibility. Bayesian model selection methods did not support the null hypothesis, however. It was found attorneys differentiate between the conditions. The rates in which legal professionals and forensic mental health evaluators experienced challenges were also higher than was expected. These positive findings show there is some degree of gatekeeping psychological assessment evidence in the courts.