Quantifying the Accuracy of Forensic Examiners in the Absence of a “Gold Standard”

Douglas Mossman, Michael D. Bowen, David J. Vanness, David Bienenfeld, Terry Correll, Jerald Kay, William M. Klykylo, Douglas S. Lehrer

This study asked whether latent class modeling methods and multiple ratings of the same cases might permit quantification of the accuracy of forensic assessments. Five evaluators examined 156 redacted court reports concerning criminal defendants who had undergone hospitalization for evaluation or restoration of their adjudicative competence. Evaluators rated each defendant's Dusky-defined competence to stand trial on a five-point scale as well as each defendant's understanding of, appreciation of, and reasoning about criminal proceedings. Having multiple ratings per defendant made it possible to estimate accuracy parameters using maximum likelihood and Bayesian approaches, despite the absence of any "gold standard" for the defendants' true competence status. Evaluators appeared to be very accurate, though this finding should be viewed with caution.