Development and effects of an MMPI--A K-correction procedure

Area of Science:

• Psychological assessment
• Clinical psychology
• Personality testing

Background:

• The K-correction factor is a widely used but debated procedure for the Minnesota Multiphasic Personality Inventory (MMPI) in adults.
• The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) includes K-correction, but the Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A) was developed using non-K-corrected scores.

Purpose of the Study:

• To derive age-appropriate K-weights for the MMPI-A.
• To evaluate if K-correction improves classification accuracy for adolescent participants into normal and clinical groups.

Main Methods:

• Discriminant function analyses were used to identify optimal K-weights for the MMPI-A's eight basic clinical scales.
• Hit rate analyses compared the classification accuracy of K-corrected versus non-K-corrected MMPI-A T scores.

Main Results:

• The study found that applying K-correction to the MMPI-A did not systematically enhance test accuracy.
• No significant improvements in classifying adolescents into normal and clinical groups were observed with K-corrected scores.

Conclusions:

• The findings do not support the routine clinical use of K-correction for interpreting MMPI-A protocols.
• Current evidence suggests standard MMPI-A interpretation without K-correction is appropriate for adolescent populations.