Assessing underreporting response bias on the MMPI-2.

The authors assess the replicability of the two-factor model of underreporting response style. They then examine the relative performance of scales measuring these styles in analog (ARD) and differential prevalence group (DPG) designs. Principal components analysis produced a two-factor structure corresponding to self-deceptive (SD) and impression management (IM) response styles. The IM factor scale and related individual validity scales were elevated among research participants instructed to fake good on the MMPI-2 as compared with participants who completed the MMPI-2 under standard instructions (ARD) and among individuals evaluated in real-life assessment contexts where underreporting is expected (DPG). Participants in DPG samples produced significantly higher SD factor and related individual scale scores than did the ARD participants instructed to fake good. These findings confirm that the MMPI-2 validity scales measure two types of underreporting styles and that these styles may operate differently in ARD versus DPG designs.