Reliability generalization: Exploring variation of reliability coefficients of MMPI clinical scales scores

This study used reliability generalization to explore the variance of scores on the Minnesota Multiphasic Personality Inventory's (MMPI's) 10 clinical scales. Reliability generalization was implemented to identify (a) typical reliability of scores across studies, (b) the variability of clinical scale score reliability, and (c) measurement factors explaining or predicting variability in MMPI clinical score reliability. The reliability coefficients for scores on the 10 scales ranged from .00 to .96. Scale 5 (Mf) appeared to have the greatest variability (SD = 0.20) and Scale 2 (D) the widest range of score reliabilities (.00 to .93). Average reliability coefficients ranged from .64 for Scale 6 (Pa) to .81 for Scale 0 (Si). Variations in MMPI clinical scale score reliabilities were best predicted by (a) MMPI form and (b) participant age groups.