MMPI-2 base rates for 492 personal injury plaintiffs: implications and challenges for forensic assessment

This study reports base rates of MMPI-2 clinical scales. PTSD scales, and validity scales for 492 personal injury plaintiffs, 230 men and 262 women. Scales studied included L, F, K, F minus K, Ds-r, Fake Bad, Ego Strength, Back F. Total Obvious minus Subtle, VRIN, and TRIN. Forensic high points resembled outpatient profiles but not the MMPI-2 psychiatric sample and shared only code type 13/31 with the normative sample. The most common two-point code type for men was 13/31, followed by 12/21 and 23/32, and for women was 13/31, followed by 23/32 and 12/21. Fifty percent of the forensic sample were code type 13/31, 12/21, or 23/32. Validity measures suggested possible malingering on approximately 20 to 30% of the profiles but the majority of profiles were valid. Validity problems discussed include attorney coaching and the congruence of plaintiff personality characteristics with the demand characteristics of litigation. Examples of attorney coaching are provided. The modal plaintiff appears to be an unhappy somatizer involved in a social context which encourages rationalization, projection of blame, and complaining.