The Minnesota Multiphasic Personality Inventory (MMPI) is the most frequently used psychological measure in the assessment of chronic pain. Since the introduction of the MMPI-2 in 1989 only two published studies have focused on cluster analysis of chronic pain patients. This study investigated MMPI-2 cluster solutions of chronic low-back pain patients. Data was collected from 2,051 chronic low-back pain patients from a multidisciplinary pain clinic in the southwestern United States. A hierarchical clustering procedure was performed on K-corrected T-scores of the MMPI-2 using the three validity and ten clinical scales. Four relatively homogeneous subgroups were identified for each sex with the MMPI-2. In general, these results replicated the findings of previous researchers using both the MMPI and MMPI-2.

The Personality Inventory for Youth (PIY) is a recently developed, multiscale assessment instrument designed specifically for adolescents between the ages of nine and 18. The purpose of this archival study was to establish clinical correlates for the PIY scales. PIY profiles were collected from 100 juvenile files at the Gainesville State School and examined in conjunction with the Child Assessment Scale (CAS) and the Personal Attitude Scale (PAS) to provide evidence of convergent and discriminant validity. Results indicate modest to moderate convergent validity according to Campbell and Fiske's criteria for construct validity; however, discriminant results indicate considerable overlap among traits which are not expected to be highly correlated.