The usefulness of multiscale inventories depends on their ability to evaluate response styles effectively, such as fake-bad (feigning) and fake-good (defensiveness) profiles. The current investigation combined validity data across clinical, nonclinical, and simulating samples to evaluate the usefulness of the Personality Assessment Inventory (PAI) negative impression (NIM)-positive impression (PIM) difference score to detect simulated profiles. In general, its effect sizes were not appreciably different from those afforded by NIM and PIM alone. Likewise, its incremental contributions in logistic regression were minimal. These results do not support the routine use of a NIM-PIM difference score in detecting response styles with the PAI.