School psychologists are routinely required to make judgments about the severity of behavior disorders in children. While federal law demands that a child exhibit an emotional problem "to a marked degree," school psychologists are given few clearcut guidelines for making judgments about the severity of students' adjustment problems. The purpose of this paper is to present a list of empirically based criteria for assessing the severity of behavior disorders in children. To this end, research on major behavior disorders in children of interest to school psychologists is reviewed.School psychologists are routinely required to make judgments about the severity of behavior disorders in children. As used herein, the term behavior disorders refers to both conduct disorders and emotional problems. Severity refers to the degree or harmful extent of the consequences of given disorders. Not only would a very severe condition have adverse effects on the individual and/or others, it would also be characterized by a poorer response to intervention and have an unfavorable outcome. Given the ubiquity of children's problems and the financial constraints of school districts, care must be exercised in rendering judgments about the severity of children's person and social difficulties. Federal law (e.g., PL 94-142) requires that a child manifest an emotional problem "to a marked degree"; some state laws demand differentiation between seriously emotionally disturbed and emotionally disturbed; yet psychologists are given few clearcut guidelines for making judgments about the severity of students' adjustment difficulties.Major texts on child psychopathology (Quay & Werry, 1986) and school psychology (Reynolds & Gutkin, 1982) do not provide explicit, systematic, integrative coverage of this important issue. Thus, despite the ever-present demand to evaluate the severity of pupils' behavior disorders, psychologists are given very little precise guidance in making judgments about the severity of children's adjustment problems.The purpose of this article is to develop a list of empirically based criteria by which psychologists can judge the severity of behavior disorders in children. To this end, the published research literature on the major behavior disorders in children that is of interest to school psychologists is reviewed. The focus of this review is limited, by and large, to a discussion of the nature of the child's condition as it relates to severity. Discussion of home (e.g., parental psychopathology), community (e.g., community disorganization), and classroom factors (e.g., pacing) are excluded, even though they influence severity of the child's disorder. Moreover, no attempt has been made to review systematically each criterion presented with respect to every psychopathological disorder of childhood as described in the Diagnostic and Statistical Manual of Mental Disorders (DSM 111-R, 1987), which devotes 68 pages to disorders usually first evident in infancy, childhood, or adolescence (excluding mood disorders and schizophrenia, ...