An item response theory analysis of the hare psychopathy checklist - Revised

Hare's Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991) is the measure of choice for measuring psychopathic personality disorder. An item response theory (IRT) approach was adopted to analyze both test and item functioning. Data from 2,067 North American participants were analyzed. The analysis confirmed that the test was appropriate for both the diagnosis of psychopathic personality disorder and for making measures of trait strength. Two correlated but distinct factors underpin scores on the PCL-R: Factor 1, Selfish, Callous, and Remorseless Use of Others, and Factor 2, Chronically Unstable and Antisocial Life style. Items related to Factor 1 are generally more discriminating and provide more information about the trait than items relating to Factor 2. Future uses of IRT procedures in the analysis of PCL-R data are discussed.