A new performance-based measure of personality functioning impairment: development and preliminary evaluation of reliability and validity

Personality functioning impairment is at the center of many dimensional models of personality. Available measures of personality functioning impairment are limited to self-report, clinician-/informant-rated, and interview methods. Although researchers have begun investigating established performance-based instruments' potential for assessing personality functioning impairment, administration and scoring of these instruments is complex and the latent variables they measure diverge from personality functioning impairment as described in the ICD-11 and the Alternative Model for Personality Disorders (AMPD) of the DSM. We address this absence by developing and psychometrically evaluating the Level of Personality Functioning Scale-Questionnaire-based Implicit Association Test (LPFS-qIAT). The LPFS-qIAT's psychometric properties were evaluated across four studies, producing initial evidence supporting the new instrument's reliability as well as its convergent, discriminant, and criterion-related validity. As the first performance-based measure of personality functioning impairment that aligns with the AMPD and, to a degree the ICD-11, that is easily administered, scored, and interpreted, the LPFS-qIAT shows potential to become a valuable tool in both research and clinical practice.