Peter Sabella III
Professor Keith Cooper
March 31, 2011
Psychopathy is an important construct in offender classification. Although several studies have suggested that there are two distinct subtypes of psychopaths, these studies have considerable limitations, including reliance on self-report measures, a failure to adequately address heterogeneity within the construct of psychopathy, and predictor-criterion contamination. A recent taxonomic study identified four subgroups of offenders, including primary and secondary psychopaths. We used cluster analysis to replicate and extend those findings to: 1) an independent sample; and 2) a PCL-R factor model that reduces predictor-criterion contamination. Additionally, we validated initial results using a novel clustering method. Results show that psychopathy subtypes are replicable across methods. Moreover, comparisons on other variables provide external validation of the subtypes consistent with prior theoretical conceptualizations.
Criminal offenders differ in important ways, and the classification of offenders into homogeneous groups has long been the subject of scientific inquiry. Such subdivision may inform efficient application of treatments and may be useful in the prediction of future dangerousness. Personality disorders are often considered useful in classifying criminal offenders. Among these, psychopathy, with its association with impulsivity, egocentricity and remorselessness, may be of particular use in offender taxonomies. Psychopathy is reported to predict both violent and non-violent recidivism as well as lack of treatment response and a variety of deficits in emotional and cognitive function. The gold standard for assessing psychopathy is the Psychopathy Checklist-Revised. Extensive research attests to the reliability and validity of the PCL-R as a measure of psychopathy. Of the different structural...