The MMPI and MMPI-2 in an outpatient sample: comparisons of code types, validity scales, and clinical scales

Two hundred (N = 200) outpatients completed MMPI (W.G. Dahlstrom, Walsh, & L.G. Dahlstrom, 1989) and MMPI-2 (Butcher, W.G. Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) items at one time, permitting comparison of alternate forms. The concordance rate for elevated codetypes was 58%; for 2-point codetypes independent of elevation, it was also 58%. Only 50% of the men compared to 66% of the women showed concordance between forms. Of the 200 cases, 72 (36%) had codetypes that were both elevated and "well defined." The concordance rate among these 71 cases was 72%. Comparison of mean raw scores for the validity and clinical scales showed a small difference for MMPI versus MMPI-2 (Form) on Scales 2 and 5, small differences for Gender on Scales 1, 2, and 3, and no Gender by Form interactions. There were significant MMPI versus MMPI-2 differences for T-scores on all scales, and there were significant Gender by Form interactions for T-scores on all scales except Scale L, Scale K, and Scale 6 (excluding Scale 5). Comparison of mean T-scores (excluding Scale 5) showed no significant differences for Gender on the 12 scales. In spite of significant mean differences, correlational analyses show correlations above .96 for the raw scores and T-scores for each gender, indicating that rank ordering of cases is maintained between forms. These results are discussed in terms of the issues for use of the MMPI-2 compared to the MMPI.