The Taxonic Latent Structure and Taxometrics in Forensic Mental Health

Recently, researchers in the field of forensic mental health have attempted to address the technical, empirical question of whether important clinical problems, such as psychopathy or malingering, constitute taxa (i.e., discrete conditions). In this paper, we provide a detailed elucidation of the foundational logic of the quantitative methods employed to answer this question, focusing on the taxometric procedures developed by Paul Meehl and colleagues. We attempt to demonstrate that research on taxonicity is hampered by (a) researchers’ unfamiliarity with or misunderstanding of the logic underlying latent variable technologies and (b) the fundamental incapacity of Meehlian procedures to provide a test of taxonicity. We conclude by discussing the utility of taxometric procedures to research in forensic mental health and, more broadly, in the field of applied psychological measurement.