TASC IS A PROGRAM DESIGNED TO REFER ARRESTED DRUG ADDICTS TO APPROPRIATE COMMUNITY BASED TREATMENT AND REHABILITATION PROGRAMS. A METHODOLOGY IS DESCRIBED FOR PERFORMING THE EVALUATION BY A PROCEDURE WHICH CLASSIFIES ADDICTS INTO HOMOGENOUS POPULATION GROUPS SHARING COMMON CHARACTERISTICS AND ESTIMATES THE VARIOUS LEVELS OF EFFECTIVENESS OF AVAILABLE TREATMENT ALTERNATIVES IN REHABILITATING THESE GROUPS. THE METHODOLOGY DEVELOPED CONTAINS A DESCRIPTION OF STUDY OBJECTIVES IN THE FORM OF RESEARCH QUESTIONS TO BE ADDRESSED, EVALUATION PROCEDURES, AND DATA REQUIREMENTS. IT IS DESIGNED TO BE ADAPTABLE TO A WIDE RANGE OF DATA. (AUTHOR ABSTRACT MODIFIED)