The question of cultural bias in assessment and diagnosis of ethnic minority clients: Let's reject the null hypothesis.

Cultural bias in the mental health assessment and psychiatric diagnosis of ethnic minorities has been asserted and challenged on the basis of clinical impression and a variety of psychometric criteria. The lack of a definitive empirical basis to resolve issues of assessment and diagnostic bias means that the null hypothesis (no bias or cross-cultural uniformity) prevails. This article argues that the traditional hypothesis to be nullified should be challenged. The consequences associated with its incorrect retention (Type II error = disservice to minority clients) may be more serious than its incorrect rejection (Type I error = misdirection to the mental health service system). If a clientcentered error is judged more serious than a service system error, then a statement of bias or crosscultural variance should be the null hypothesis until such time as empirical data suggest otherwise. The presumptions of valid measurement of psychological symptomatology and accurate diagnosis of psychiatric disorders are fundamental to the integrity of mental health research and to the delivery of effective mental health services. The fourth edition of the American Psychiatric Associations^ Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; 1994) reflects an increasing recognition of the importance of considering the cultural diversity of clients in rendering psychiatric diagnoses. Yet limited empirical data and even sparser theoretical preconceptions hinder researchers, professional practitioners, and policymakers in deciding whether or not—and, if so, how—a culturally informed mental health assessment ought to take place (Lopez, 1988; Lopez Malgady, 1994). This issue is of special concern because effective psychopharmacological and psychotherapeutic treatment planning and continuity of care are predicated, in part, on accurate evaluation of symptom severity and diagnosis.