Generalizability of underreporting across self-report measures in a police preemployment sample
Response styles detected by the Minnesota Multiphasic Personality Inventory – 2 - Restructured Form (MMPI-2-RF) Validity scales generalize to other self-report measures (Forbey, Lee, Ben- Porath, Arbisi, & Gartland, 2013). However, no research has investigated the generalizability of underreporting (UR) in preemployment settings. Thus, we investigated if UR detected by MMPI- 2-RF L-r (Uncommon Virtues) and K-r (Adjustment Validity) scores generalized to the California Psychological Inventory (CPI; Gough & Bradley, 1996). Using data from a sample of 1,570 (Men = 1,372, Women = 198) police candidates who completed the MMPI-2-RF and CPI as part of a preemployment evaluation, we assigned individuals to UR or Within Normal Limits (WNL) groups. We operationalized UR in three ways: 1) L-r > 80; 2) K-r = 72; and 3) L-r > 80 and K-r = 72. WNL groups were created by randomly selecting a matched subsample from the larger WNL sample. We calculated t-tests contrasting the UR and WNL groups’ scores on the MMPI-2-RF Restructured Clinical (RC) and CPI scales. Consistent with Forbey et al. (2013), results suggested that UR detected by scores on L-r and K-r led to suppression on some RC (3 to 9 scales depending on UR definition, d’s = .27 – 1.20) and CPI (6 to 12 scales depending on UR definition, d’s = .17 – 1.52) scales. Results suggested suppression was more consistent for the UR group defined only by scores on K-r (9/9 RC scales and 12/ 20 CPI scales) than for the groups defined using L-r (3 or 4/9 RC scales and 6 or 7/20 CPI scales). The sensitivity of K-r when compared to L-r may be a result of floor and ceiling effects. Nonetheless, results of this study suggest potential UR detected in police candidates by scores on K-r are likely to be generalizable to other instruments administered during an evaluation.