Susceptibility of the Self-Report Psychopathy Scale (SRP 4) to Response Distortion and the Utility of Including Validity Indices to Detect Deception

Public Significance Statement People can manipulate their responses on self-report scales meant to measure psychopathic traits, which may negatively affect conclusions that are made based on those responses. Self-report psychopathy scales should consider including ways of identifying people who may be intentionally responding dishonestly. Self-report psychopathy scales are increasingly used in research and practice despite criticisms that they may be susceptible to response distortion and bias. We assessed the utility of including the Virtuous Responding (VR) and Deviant Responding (DR) validity scales from the Psychopathic Personality Inventory-Revised (PPI-R) for identifying underreporting and overreporting, respectively, on both the full and short-form versions of the Self-Report Psychopathy scale (SRP 4 and SRP-SF) in a pre/post experimental design. Using a sample of 384 male community members and a clinical comparison group of 99 males from a forensic outpatient program, we demonstrated that SRP scores were more susceptible to overreporting than underreporting, and that overreporting significantly and negatively affected convergent validity. Finally, baseline psychopathy scores were unrelated to successful response distortion (i.e., changing scores in correct direction while remaining undetected by the validity scales). It is recommended that assessments using self-report psychopathy scales consider including validity indices to detect response distortion. In doing so, it will be important to consider that general impression management may be conceptually distinct from specific forms of response distortion, such as the intentional amplification or minimization of psychopathic traits.