Examining the Structure and Validity of Self-Report Measures of Alternative Model for Personality Disorders Criterion A.

The Level of Personality Functioning Scale (LPFS) operationalizes Criterion A of the Alternative Model for Personality Disorders. Despite progress in LPFS measurement development and validation, there is a lack of research, and some disagreement, concerning structural, convergent, and incremental validity of LPFS self-report measures. The present study aimed to compare the LPFS Self-Report, LPFS Self-Report of Criterion A, and LPFS Brief Form. Internal structure was assessed through principal component analyses, factor analyses, and bifactor analyses of unidimensionality. Associations with both pathological and basic personality characteristics among the LPFS measures were explored. Incremental validity of LPFS severity in predicting pathological personality outcomes controlling for basic personality traits, and the reverse, were examined. Results suggest a unidimensional structure robustly associated with other pathological personality assessments. LPFS severity and basic personality traits mutually offered unique explanatory power. We discuss the implications of assessing personality pathology using LPFS self-report measures.