Criterion-related validity of the Psychopathic Personality Inventory in a prison sample.

Abstract

The Psychopathic Personality Inventory (PPI; S. O. Lilienfeld & B. P. Andrews, 1996), a self-report measure of psychopathic personality features, and R. D. Hare's (1991) Psychopathy Checklist-Revised (PCL-R) were administered to adult youthful offender prison inmates (N = 50). As hypothesized, PPI scores were significantly correlated with scores on the PCL-R, providing evidence of concurrent validity for the PPI. Moreover, unlike existing self-report psychopathy measures, the PPI showed a moderate and positive correlation with PCL-R Factor 1 (i.e., the core personality traits of psychopathy). Discriminant function analysis using the optimal PPI total score value to predict PCL-R classifications of psychopath (n = 10) and nonpsychopath (n = 40) resulted in accurate classification of 86% of the cases (sensitivity =.50, specificity =.95). Results are discussed in terms of the relative merits of these 2 measures of psychopathy and the validation of the PPI for clinical use.