Comparing Measures of Criterion A to Better Understand Incremental Validity in the Alternative Model of Personality Disorders

The Alternative Model of Personality Disorders distinguishes between the severity of personality dysfunction (Criterion A) and individual differences in personality disorder expression (Criterion B). Several Criterion A measures exist, but few studies have compared these measures with each other. Moreover, debates about whether the constructs of Criteria A and B are redundant (i.e., weak incremental validity) should be framed around how different Criterion A measures perform relative to others. This study of 204 undergraduate students evaluated multiple measures of Criterion A. These measures were strongly correlated with Criterion B, but evidenced incremental validity (39% of outcomes, 5% average additional variance explained) with outcomes of psychopathology and interpersonal impairments, and less consistent incremental validity with suicidality, aggression, and mental health utilization. We discuss how these results inform the construct of Criterion A relative to Criterion B and evaluate strengths/weaknesses of Criterion A measures.