Effects of two MMPI-2 validity scales on basic scale relations to external criteria

Area of Science:

• Psychological assessment
• Clinical psychology
• Psychopathology research

Background:

• Clinicians frequently utilize Minnesota Multiphasic Personality Inventory (MMPI) and MMPI-2 validity scales.
• The MMPI-2 offers various scales to assess response validity.
• Understanding the utility of specific MMPI-2 validity scales is crucial for accurate interpretation.

Purpose of the Study:

• To evaluate the effectiveness of two MMPI-2 validity scales: the K scale and the Variable Response Inconsistency (VRIN) scale.
• To examine the impact of K-correction and VRIN scale exclusion on MMPI-2 clinical scale correlations with external criteria.
• To assess these scales' utility in a sample of psychiatric inpatients.

Main Methods:

• Analyzed data from 692 psychiatric inpatients.
• Compared correlations between MMPI-2 clinical scales and external criteria (self-report and clinician ratings) using K-corrected and non-K-corrected scores.
• Examined the effect of excluding MMPI-2 protocols with VRIN T-scores >= 80.

Main Results:

• The K-correction procedure did not enhance the correlation between MMPI-2 clinical scales and external criteria compared to non-K-corrected scores.
• MMPI-2 protocols with VRIN T-scores >= 80 showed reduced correlations with psychopathology measures.
• Excluding high VRIN scores generally improved the relationship between MMPI-2 scales and external criteria.

Conclusions:

• The K-correction procedure may not consistently improve the validity of MMPI-2 interpretations in this patient population.
• The VRIN scale is a valuable tool for identifying potentially invalid MMPI-2 protocols in psychiatric inpatients.
• Excluding protocols with elevated VRIN scores can enhance the accuracy of MMPI-2 findings related to psychopathology.