SUBJECTS IN THE STUDY WERE 311 MEN WHO ENTERED A COMMUNITY BASED HALF-WAY HOUSE AT LEAST SIX MONTHS PRIOR TO THE STUDY. THIS GROUP WAS DIVIDED INTO TREATMENT COHORTS AND PERFORMANCE WAS FOLLOWED FOR SIX MONTHS AFTER ENTRY INTO THE PROGRAM TO ASCERTAIN SUCCESSES AND FAILURES. FAILURE WAS DEFINED AS ADMINISTRATIVE REMOVAL ESCAPE, IN-PROGRAM ARREST, AND SPECIFIC PROGRAM ARRESTS. THE DEPARTMENT OF CORRECTIONS (DCDC) DEFINED THREE DIFFERENT PROGRAMS WHEREAS THE NARCOTIC TREATMENT ADMINISTRATION (NTA) DEFINED TWO. RECIDIVISM RATES WERE DETERMINED FOR EACH TREATMENT GROUP USING BOTH DCDC AND NTA DEFINITIONS. FOR EITHER DEFINITION, THE TREATMENT GROUPS USING METHADONE SHOWED A SIGNIFICANTLY HIGHER SUCCESS RATE THAN THE ABSTINENCE GROUPS - SUCCESS RATES FOR METHADONE PATIENTS WERE APPROXIMATELY 74 PERCENT FOR THE TWO DCDC METHADONE COHORTS AND 82 PERCENT FOR THE NTA METHADONE COHORT. SUCCESS RATES FOR THE ABSTINENCE SUBJECTS, REGARDLESS OF DEFINITION WERE APPROXIMATELY 50 PERCENT. (AUTHOR ABSTRACT)