One of the most common personality inventories employed in psychology and psychiatry. It uses a series of questions to make diagnoses according to standard psychiatric clinical criteria. Among the most cited scales reported in the PDD literature are psychopathy and social introversion-extroversion scales, both of which have been shown to influence physiologic arousal levels, particularly in the electrodermal response. Evaluation and interpretation of the MMPI is generally based on profiles resulting from individual scales. Test-retest validity for the MMPI averages above 70%, though the validity of the individual personality scales has not been conclusively demonstrated.