Psychometric Performance of the Miller Forensic Assessment of Symptoms Test (M-FAST) in Veteran PTSD Assessment

This study examined the psychometric properties of a widely used measure of symptom exaggeration, the Miller Forensic Assessment of Symptoms Test (M-FAST, Miller, 2001), in a sample of 209 (83.7% male) trauma-exposed veterans (57.9% probable current posttraumatic stress disorder; PTSD). M-FAST total scores evidenced acceptable internal consistency, but several subscales showed poor internal consistency. Factor analytic and item-response theory analyses identified seven poorly performing items. Comparisons with other measures of psychopathology and response validity (including subscales from the Minnesota Multiphasic Personality Inventory-2 Restructured Form) revealed that M-FAST scores were highly correlated with indices of psychopathology while less strongly associated with measures of symptom over-reporting. Empirically and clinically-derived (using a follow-up testing-the-limits procedure) revised M-FAST scores failed to improve the measure’s psychometric performance. Results raise concerns about the validity of the M-FAST for identifying malingering in veterans with PTSD and carry implications for access to care and forensic evaluations in this population.