MASSACHUSETTS HALFWAY HOUSES, INC. (MHHI) WAS FOUNDED IN 1964 TO PROVIDE A RESIDENCE FOR MALE EX-OFFENDERS FROM STATE AND FEDERAL PRISONS. THIS STUDY IS THE FIRST COMPONENT OF A THREE-PART EVALUATION OF RESIDENTS RELEASED FROM MHHI ON A PRERELEASE BASIS DURING 1977 AND 1978. IT INCLUDES INFORMATION ON THE MOVEMENT OF POPULATIONS IN AND OUT OF MHHI PROGRAMS, PROGRAM TERMINATION DATA, AND STATISTICAL BREAKDOWNS OF BACKGROUND CHARACTERISTICS OF PROGRAM PARTICIPANTS ACCORDING TO THE MHHI FACILITY IN WHICH THEY PARTICIPATED. THE SAMPLE STUDIED INCLUDED 182 RESIDENTS RELEASED FROM MHHI FACILITIES IN 1977 AND 141 RELEASED IN 1978. THOSE RESIDENTS STUDIED ARE SEPARATED INTO THOSE COMPLETING THE STAY AT MHHI AND RELEASED TO THE STREETS AND THOSE WHO DID NOT COMPLETE THE PROGRAM AND WERE RETURNED TO THEIR SENDING INSTITUTIONS. FOR 1977, 137 RESIDENTS WERE PROGRAM COMPLETERS (75 PERCENT COMPLETION RATE) AND 45 RESIDENTS WERE PROGRAM NONCOMPLETERS (25 PERCENT NONCOMPLETION RATE); FOR 1978, 98 RESIDENTS WERE PROGRAM COMPLETERS (71 PERCENT COMPLETION RATE) AND 41 WERE NONCOMPLETERS (29 PERCENT NONCOMPLETION RATE). REASON GIVEN FOR A RETURN TO A HIGHER SECURITY INSTITUTION WERE INABILITY TO ADJUST TO THE PROGRAM, VIOLATION OF HOUSE RULES, AND ATTEMPTED OR ACTUAL ESCAPES. EXTENSIVE TABLES ARE PROVIDED.