The notion of intervention strategies is introduced in this paper to explain why and when certain change efforts are successful. It is argued that the choice of control points and the selection of control linkages are determined by characteristics of the task in the implementing agency. Many implementation failures can be attributed to the selection of the wrong control point and the wrong linkage. Linkage refers to the kind of reporting required and the kind of positive or negative inducements used. Control points are selected as the relevant variable, whether implementation controls are mainly exercised on input, output, or process variables. Input controls relate to allocated funds and characteristics of the professionals and are associated with adaptive implementation. Output controls involve the implementer in saying something about what has been done and can either enlarge or reduce the implementer's discretion depending on the specificity of disclosure. Process controls are directed at internal behavior and are concerned with the way services or products are provided, thus reducing day-to-day discretion. This paper focuses on situations where the task does not always lend itself to routinization and where professional discretion is important. The implementation of the Education for All Handicapped Children Act of 1975 is selected to illustrate the unforeseen consequences of inappropriate intervention strategies. (Author/MLF)