Empirical literature on the relationship between neuropsychological impairment and scores on the MMPI and the MMPI-2 illustrates the decisionmaking process used by forensic neuropsychologists. Although empirical support for the relevance of MMPI data to clinical interpretation has been demonstrated, cautions extend to several methodological limitations in research studies, such as small sample size and experimental error. Before an expert testifies regarding MMPI or MMPI-2 results, many factors need to be anticipated and considered. Knowledge of base rates ensures that reported changes in personality functioning do not constitute idiosyncratic phenomena. Clinical interview elicits important background information, especially regarding premorbid functioning. Predictions of the rate of emotional recovery take into account type and severity of brain damage, current level of adaptive functioning, degree of functional impairment, and personal factors such as age and educational level. Forensic expertise requires clinical experience and the ability to systematically weigh all relevant factors and compare them to available base rates, the individual's baseline functioning level, and normative standards. 70 references