The Personality Pathology Dimensions Assessment Questionnaire (DAPP-BQ) is a self-report tool used to assess the characteristics of personality disorder. However, its diagnostic validity has not been investigated in Iranian samples. The main purpose of this study was to investigate the diagnostic validity of the Personality Pathology Dimensions Questionnaire (DAPP-BQ) in couples using sensitivity coefficient and clarity-orientation. The method of this research, which is in the field of psychometric designs, is a subset of methodological studies. The statistical population of the study consisted of all couples referred to counseling centers in Tehran, of which 240 couples (120 as clinical group and 120 as normative group) were selected using available purposive sampling. In the present study, in order to investigate the diagnostic validity of the mentioned instrument with an emphasis on the cut-off point method, sensitivity coefficient and clarity orientation have been used. The findings showed that the scales of "intimacy disorder" and "low social relationships" from the dimension of "social avoidance", "conduct disorder", "narcissism" and "rejection" from the dimension of "antisocial behavior", "cognitive disorder", "insecure dependence" and "stubbornness and disobedience" from the dimension of "emotional disorder" and "impulsivity" from the dimension of "impulsive behavior" using both methods have diagnostic validity and can distinguish the clinical group from the normative group.
