Development and validation of an adjective check list to assess the Millon personality types in a normal population

A 405-item experimental Personality Adjective Check List (PACL) was refined into a 153-item form to assess the personality types outlined by Millon (1969, 1981) in a normal population. Scale construction and validation followed a method outlined by Loevinger (1957, 1972). Nine scales were developed based on the responses of 459 men and women, one for each of Millon's eight basic personalities plus an Experimental scale measuring aspects of his three more severe types. Extensive reliability and validity analyses were conducted involving over 2,200 men and women from across the United States, including a factor analysis of scales. These revealed good internal consistency for each scale, good test-retest reliability over a 3-month period, adequate factor structure, and good convergent and discriminant validity based on self-report data. Results indicated that Millon's basic types exist in normal form much as they are postulated to exist as disorders. Research efforts focusing on Millon's theory as it applies to normals may bring a more complete understanding of the entire spectrum of personality.