THIS STUDY WAS BASED ON FIELD WORK CONDUCTED AT FOUR HALFWAY HOUSES FOR ALCOHOLICS IN THE BOSTON AREA TO TEST THE HYPOTHESIS THAT THE EFFECTIVENESS OF A HOUSE IN CREATING AND MAINTAINING IN ITS GUESTS THE BEHAVIORAL CHANGE WHICH LEADS TO SOCIAL REINTEGRATION IS INVERSELY PROPORTIONAL TO ITS BUREAUCRATIC EFFICIENCY. FOUR TARGET FACILITIES WERE RANKED ACCORDING TO AN 'INDEX OF INSTITUTIONAL ATMOSPHERE,' MEASURED BY THE EXISTENCE OF WRITTEN RULES, MANDATORY MEETINGS, IMPERSONAL AND DISTANT ATTITUDES OF THE STAFF, DOOR CONTROLS, ACCESS TO THE KITCHEN, AND TREATMENT SESSIONS CONDUCTED ON THE PREMISES. THE HALFWAY HOUSE WITH THE LOWEST SCORE ON ALL THE ABOVE POINTS WAS FOUND TO HAVE THE HIGHEST NUMBER OF SUCCESSFUL CURES, MEASURED BY THE GUESTS' LENGTH OF STAY, THEIR STATE OF ABSTINENCE AT THE TIME OF DEPARTURE, AND THE LENGTH OF THEIR PERIOD OF ABSTINENCE AFTER DEPARTURE. THE RATE OF READMISSION WAS ALSO INVERSELY PROPORTIONAL THE NUMBER OF POINTS SCORED BY THE HALFWAY HOUSES ON THE INDEX OF INSTITUTIONAL ATMOSPHERE. THEREFORE, AN INFORMAL HOMELIKE ATMOSPHERE APPEARS TO BE THE MOST THERAPEUTICALLY EFFECTIVE IN TREATING AND REHABILITATING ALCOHOLICS. (LGR)