Reviewed analogue research that investigated bias in school psychologists' and other educators' special education diagnostic and placement decisions. Methodological and theoretical concerns related to analogue studies are addressed subsequently. Finally, recommendations for future research are provided.The accurate determination of the need for special education services is a prerequisite to the provision of such services. Given that some groups of children (e.g., minorities, males) have been disproportionately represented in special education (SE) programs, numerous questions have been raised regarding bias in SE decision-making practices.Bias usually "implies prejudice . . . or inaccuracy in clinical judgment" (Lopez, 1989, p. 184). Although there is disagreement over the term, bias will be used herein to refer to systematic, divergent decisions based upon comparable information (e.g., assessment data) as a function of group membership (e.g., racial, gender, or cultural differences) (Cleary, Humphreys, Kendrick, & Wesman, 1975). Racial bias would thus be demonstrated if members of one ethnic group were disproportionately recommended for SE programs when all other variables (e.g., school achievement) were equal.The search for factors related to bias in assessment outcomes has proceeded through two major stages of development. Initial efforts focused narrowly on assessment instruments, primarily standardized intelligence tests.