The inconsistency of inconsistency scales: a comparison of two widely used measures.

This study compared the inconsistent responding validity scales of the Personality Assessment Inventory (PAI) and the Psychopathic Personality Inventory (PPI)/PPI-Revised (PPI-R) in two correctional samples to determine the extent to which they overlap in identifying invalid profiles. Results revealed substantial differences in the way the inconsistent responding validity scales of these measures performed. In particular, the PAI identified far fewer participants as having responded inconsistently compared with the PPI/PPI-R. We discuss the implications of our findings for clinical practice, and potential concerns with the use of a single measure to identify inconsistent responding in clinical practice and research.