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was coded directly from the official Criminal Profile Reports (CPR) and the Psychological Assessment Reports (PAR) included in the institutional files. These two documents are considered to be the most important and informative files within each offender’s case file for describing in detail the offender’s violent crimes. The CPR is written by a case management officer and is based on the official police report (submitted to the prose- cutor to allow charges to be laid) and court information (e.g., submissions by the prosecutor). The report is an objective description of the actual crime as a result of a thorough investigation and court testimony. Within the CPR, an official, detailed description (typically 1–2 pages in length) is provided for each serious offense. The PAR is a detailed assessment of the offender’s psychological status and description of violent crimes, written by a psychologist. The extensiveness of the documents contained within each inmate’s institutional file clearly was sufficient for completing both the homicide coding and the additional 29 PCL–Rs.
Procedure PCL–R reliability. Interrater reliability of the PCL–R assessments for
the entire sample was examined in two ways. First, 21 offenders (16.8%) were randomly selected for dual coding. In these cases, with the exception of the PAR documenting the original PCL–R score, all file information available on each offender was made available to the blind coder. This check ensured that the original PCL–R scores were accurate, as expected given that the original raters were all highly trained psychologists. For a second reliability check, a set of 33 cases was randomly selected for dual coding. However, for these cases, all details pertaining to the current homicide offense were completely removed prior to coding. Although this practice for assessing reliability has rarely been adopted in psychopathy studies, we felt that it was an important measure. The rationale for this second test of reliability was that coding in the absence of the homicide description would circumvent the possibility of “circularity” or contami- nation in scoring the PCL–R. In other words, just as it was necessary for homicide coding to be done without knowledge of whether the offender was psychopathic (see below), we felt that it was important to demonstrate that PCL–R scores were not unduly influenced by knowledge of the details of the homicide. Homicide coding scheme. The characteristics of the 125 homicides
were coded on the basis of pertinent information in the offenders’ files. To avoid possible rating bias, the coder was kept unaware of the PCL–R score (removed prior to coding). Overall, 13 of the 125 (10.4%) offenders had committed more than one homicide; 11 offenders had committed two homicides, and 2 offenders had committed three homicides. However, due to a general lack of file information concerning “historical” homicides,
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some of which were from decades earlier, only the most recent homicide was coded.
To examine in detailed (rather than dichotomous) fashion whether the degree of instrumentality and reactivity associated with homicide was associated with level of psychopathy, each homicide was rated on a Likert-type scale with possible ratings ranging from 1 to 4. Based on Cornell et al.’s (1996) coding criteria for instrumental and reactive aggres- sion, as well as an extensive literature review, this was conceptualized as a continuum as follows:
