Current and projected educational developments (such as the increasing demand for school psychological services) as well as the traditional friction between teaching and psychological services, are briefly considered as a backdrop against which to present a general diagnostic intervention services model. The model identifies three levels of school psychological services: (1) primary, which focus on the entire school population and which are primarily preventive and developmental; (2) secondary, which apply to vulnerable school populations, eg. lower class minority groups, and are heavily ameliorative and compensatory in emphasis; and (3) tertiary, which service children definitely diagnosed as problematic, and which focus on remediation and therapy. Salient characteristics of class based on the model are listed. The implementation of a variation of the diagnostic-intervention class model in an Austin, Texas elementary school which serves disadvantaged children is described, and results and observations presented. (TL)