A Comparison of Selected MMPI-2 and MMPI-2-RF Validity Scales in Assessing Effort on Cognitive Tests in a Military Sample

Using a relatively new statistical paradigm, Optimal Data Analysis (ODA; Yarnold & Soltysik, 2005), this research demonstrated that newly developed scales for the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) and MMPI-2 Restructured Form (MMPI-2-RF) specifically designed to assess over-reporting of cognitive and/or somatic symptoms were more effective than the MMPI-2 F-family of scales in predicting effort status on tests of cognitive functioning in a sample of 288 military members. ODA demonstrated that when all scales were performing at their theoretical maximum possible level of classification accuracy, the Henry Heilbronner Index (HHI), Response Bias Scale (RBS), Fake Bad Scale (FBS), and the Symptom Validity Scale (FBS-r) outperformed the F-family of scales on a variety of ODA indexes of classification accuracy, including an omnibus measure (effect strength total, EST) of the descriptive and prognostic utility of ODA models developed for each scale. Based on the guidelines suggested by Yarnold and Soltysik for evaluating effect strengths for ODA models, the newly developed scales had effects sizes that were moderate in size (37.66 to 45.68), whereas the F-family scales had effects strengths that ranged from weak to moderate (15.42 to 32.80). In addition, traditional analysis demonstrated that HHI, RBS, FBS, and FBS-R had large effect sizes (0.98 to 1.16) based on Cohen's (1988) suggested categorization of effect size when comparing mean scores for adequate versus inadequate effort groups, whereas F-family of scales had small to medium effect sizes (0.25 to 0.76). The MMPI-2-RF Infrequent Somatic Responses Scale (F-S) tended to perform in a fashion similar to F, the best performing F-family scale.