Why were non-K-corrected T scores re-introduced in the Extended Score Report?
Research indicates that the K correction does not enhance validity and that in some cases validity is actually attenuated by applying the K correction to the Clinical Scales. Non-K-corrected T scores allow interpreters to examine the relative contributions of the clinical scale raw score and the K correction to K-corrected clinical scale T scores. This information may be particularly helpful when the K score deviates substantially from the average T-score range (<40 or >65). Because all other MMPI-2 scores that aid in the interpretation of the Clinical Scales (the Harris-Lingoes Subscales, Restructured Clinical Scales, Content and Content Component Scales, PSY-5 Scales, and Supplementary Scales) are not K-corrected, they can be compared most directly with non-K-corrected T scores.
