Development and initial validation of the Scale of Scales (SOS) overreporting scores for the MMPI family of instruments

ABSTRACT

Overreporting is a common problem that complicates psychological evaluations. A challenge facing the effective detection of overreporting is that many of the identified strategies (e.g., symptom severity approaches; see Rogers & Bender, 2020) are not incorporated into broadband measures of personality and psychopathology (e.g., Minnesota Multiphasic Personality Inventory family of instruments). While recent efforts have worked to incorporate some of these newer strategies, no such work has been conducted on the MMPI-3. For instance, recent symptom severity approaches have been used to identify patterns of multivariate base rate “skyline” elevations on the BASC, and similar strategies have been adopted into the PAI to measure psychopathology (Multi-Feigning Index; Gaines et al., 2013) and cognitive symptoms (Cognitive Bias Scale of Scales; Boress et al., 2022b). This study used data from a simulation study (n = 318) and an Active-Duty (AD) clinical sample (n = 290) to develop and cross-validate such a scale on the MMPI-2-RF and MMPI-3. Results suggest that the MMPI SOS (Scale of Scales) scores perform equitably to existing measures of overreporting on the MMPI-2-RF and MMPI-3 and incrementally predict a PVT-classified “known-group” of Active Duty service members. Effects were generally large in magnitude. Classification accuracy achieved desired specificity (.90) and approximated expected sensitivity (.30). Implications of these findings are discussed, which emphasize how alternative overreporting detection strategies may be useful to consider for the MMPI. These alternative strategies have room for expansion and refinement.

KEYWORDS:

• MMPI
• symptom validity
• overreport
• Scale of Scales

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1. These three feigning groups have been shown to perform indistinguishably from each other in previous research (see Agarwal et al., 2023; N. M. Morris et al., 2021) and thus were combined into one general feigning group for the current study.

2. ²We explored if the inclusion of the Specific Problems scale CYN in the computation of the MMPI-3 SOS scores improved the scales effectiveness given that RC3 was included in MMPI-2-RF RC scale-based computations of our SOS scores but not in MMPI-3 SOS scores computations (consistent with changes in the classification of CYN across test versions). Across feigning and honest groups, t-tests comparing mean SOS scores derived using MMPI-3 RC scales alone vs MMPI-3 RC scales with CYN produced identical effect sizes (g = 1.30). Similarly, MMPI-3 SOS Mean scores with and without CYN produced identical Area Under the Curve estimates (AUC = .78).

3. As noted above, we initially tested a number of substantive scale combinations (i.e., HO and RC scale scores, with and without RCd) for inclusion in our SOS scoring within a simulated feigning dataset (N. M. Morris et al., 2021). Preliminary analyses evaluating these potential combinations overwhelmingly suggested equivalent effectiveness and we elected to use RC scores alone without RCd for conceptual reasons. Mean differences and classification statistics for these alternative scoring methods are available from the test authors upon request.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.