Cross-national reliability study of a schedule for assessing personality disorders

The inter-rater reliability of a schedule used to assess personality disorders was examined. The Personality Assessment Schedule (PAS) involves an interview with both the patient and a close informant and the ratings for the informant are given most weight in the final scoring. Videotaped interviews with 23 psychiatric patients, most of whom had a clinical diagnosis of personality disorder, and a close informant were scored by seven raters, four in the United Kingdom and three in the United States. Overall inter-rater reliabilities (using the intraclass correlation coefficient, RI) were generally good to excellent for each of the 24 personality variables tested, ranging between .66 and .94 for informants and between .51 and .91 for subjects. Corresponding reliability coefficients for overall mean PAS scores were .82 and .75, respectively. Consistent with these findings, there was little bias between the scores of American and British raters, although there was some tendency for American raters to score higher for the trait of eccentricity and lower for the trait of conscientiousness than was true for British raters. There was less bias for informants' ratings than for those of subjects. In a second set of analyses, it was shown that inter-rater reliability levels (using the Kappa statistic) were also good to excellent (.6 to .8) for the categorical diagnosis of personality disorder. These results, taken together, demonstrate that abnormal personality can be reliably assessed by both British and American raters.