The Mainstream Assistance Team (MAT) project is a 3-year research program designed to develop, implement, and validate a prereferral intervention model. The model is a least-restrictive, preventative, ecologically-based, problem-solving approach, using a multidisciplinary team composed of a school psychologist, special educator, and general educator. The program's rationale focuses on the increasing numbers of identified mildly handicapped students and the importance of prereferral assessment and intervention in general education classrooms. The social, political, and bureaucratic dimensions of the Tennessee school district setting for which the MAT was developed are considered in the program's design. Major dimensions of the MAT include: behavioral consultation; component analyses of three increasingly inclusive versions of the stages of behavioral consultation (problem identification, problem analysis, plan implementation, and problem evaluation); written scripts to guide consultants' verbal behavior during interviews or meetings; and outcome measures. The implementation process involves selecting schools, consultants, teachers, and pupils; training the consultants; assigning teachers and scripts to consultants; and developing specific procedures. Evaluative data show apparent inconsistency between teacher ratings and classroom observations, and three explanations for this are discussed. Future directions for the MAT project focus on strengthening project-related interventions by requiring use of contingency contracts and data-based monitoring procedures. (JDD)