Evaluating the Similarity of MMPI-2 and MMPI Profiles: Reply to Dahlstrom and Humphrey

We review issues that have arisen in exchanges with Dahlstrom and Humphrey (Dahlstrom & Humphrey, 1996; Humphrey & Dahlstrom, 1995) about assessing the comparability of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) and the MMPI. We point out the limitations of Q correlations (without contending that D² is "the only legitimate function of profile comparability," as Dahlstrom and Humphrey, 1996, p. 350, claim we do), and explain why Dahlstrom and Humphrey's (1996) new Q-correlational results, correctly interpreted, are consistent with our own previous observations and conclusions. We stress again the importance of both overall profile elevation and profile "definition" in making code-type assignments. Nonrestrictive code types ignore these profile characteristics, and their use needlessly lowers MMPI-2/MMPI code-type congruences and raises the incidence of profile misinterpretations. Our recommendation of well-defined MMPI-2 code types stands.