Development and validation of an inconsistent responding scale for an abbreviated version of the Psychopathic Personality Inventory — Revised
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© 2015 Elsevier Ltd. An abbreviated version of the Psychopathic Personality Inventory - Revised (PPI-R; Lilienfeld & Widows, 2005) was recently developed to facilitate assessment in settings with time constraints (PPI-R-40; Eisenbarth, Lilienfeld, & Yarkoni, 2015). However, the shortened measure precludes use of the Inconsistent Responding (IR) scales embedded in the full PPI-R. In the present study, we develop a new inconsistent responding scale for the PPI-R-40 and provide initial evidence of its reliability and validity in a sample of undergraduate students (N = 974) and a sample of forensic psychiatric inpatients (N = 200) that previously completed the PPI-R. Across both samples our newly constructed scale, the Inconsistent Responding-Short-10 (IRS-10), correlated moderately with existing IR scales of the PPI-R (rs = .35-48) and was associated with several external indicators of inattentiveness, including trait conscientiousness among undergraduates and symptoms of psychosis among forensic inpatients. ROC curve analyses demonstrated that IRS-10 scores strongly discriminated between respondent and randomly-generated protocols and tentative cut scores for profile invalidity are proposed based on rates of sensitivity and specificity. Overall, our findings suggest that the IRS-10 is capable of detecting inconsistent or careless completion of the PPI-R-40 and may improve the integrity of future research and clinical practice with this instrument.
author list (cited authors)
Kelley, S. E., Edens, J. F., Donnellan, M. B., Ruchensky, J. R., Witt, E. A., & McDermott, B. E.