Validation of the Millon Clinical Multiaxial Inventory for Axis II disorders: does it meet the Daubert standard?

Relevant to forensic practice, the Supreme Court in Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) established the boundaries for the admissibility of scientific evidence that take into account its trustworthiness as assessed via evidentiary reliability. In conducting forensic evaluations, psychologists and other mental health professionals must be able to offer valid diagnoses, including Axis II disorders. The most widely available measure of personality disorders is the Million Clinical Multiaxial Inventory (MCMI) and its subsequent revisions (MCMI-II and MCMI-III). We address the critical question, "Do the MCMI-II and MCMI-III meet the requirements of Daubert?" Fundamental problems in the scientific validity and error rates for MCMI-III appear to preclude its admissibility under Daubert for the assessment of Axis II disorders. We address the construct validity for the MCMI and MCMI-II via a meta-analysis of 33 studies. The resulting multitrait-multimethod approach allowed us to address their convergent and discriminant validity through method effects (Marsh, 1990). With reference to Daubert, the results suggest a circumscribed use for the MCMI-II with good evidence of construct validity for Avoidant, Schizotypal, and Borderline personality disorders.