Misconceptions and misuse of the MMPI-2 in assessing personal injury claimants

The MMPI-2 enjoys widespread popularity in the psychological assessment of personal injury claimants, in part due to its long history, massive research literature, strong empirical basis, and the availability of commercial interpretative and scoring services. However, the relative paucity of studies examining the forensic role of the MMPI-2, raises concerns about the applicability of traditional interpretative guidelines in the medicolegal arena. This paper analyses MMPI-2 protocols of 2080 cases derived from a forensic psychiatric practice in Brisbane, Australia. The data presented here challenges these traditional MMPI-2 interpretations and calls into question assumptions and commonly employed techniques when applied in this setting. In particular, the validity of codetype-based interpretations, the role the MMPI-2 plays in differential diagnosis, and assumptions regarding diagnostically-specific patterns on the test are challenged. MMPI-2 interpretative cookbooks, computer report-writers, adherence to the intent of the test-developers, and appeals to authority are inadequate substitutes for empirical accuracy, and an active hypothesis-testing interpretative approach, based upon setting-specific base-rate data, is recommended.