Abstract
This article discusses the difficulties school psychologists have experienced in assessing behavior disorders in the schools. These difficulties are discussed in light of training and practice of school psychologists in this area as well as current definitions and conceptualizations of childhood psychopathology. An alternative definition of behavior disorders is presented and discussed in the context of an assessment model which is designed to guide assessment practice. Application of this model for behavior disorder assessment is discussed using five “principles” which should guide assessment practice for behavior disorders. These “principles” are termed: (a) Principle of Problem Solving, (b) Principle of Functional Analysis, (c) Principle of Multiple Operationalism, (d) Principle of Generalizability, and (e) Principle of Social Validity.