Stability of MMPI scale scores within four codetypes across forty years

The changes in the standard validity and clinical scales on the Minnesota Multiphasic Personality Inventory (MMPI) were examined within four frequently occurring codetypes (Spike 4, 2-4/4-2, 2-7/7-2, and 6-8/8-6) in samples of psychiatric patients over a time span of 40 years. The validity and clinical scale scores within these four codetypes were very stable over this time span with differences in the range of only a few T-score points. These results are very similar to those reported by Pancoast and Archer (1989) who found remarkable stability in the MMPI scale scores of normal adult samples across 40 years.