BOTH GROUPS WERE MADE UP OF MALE INMATES IN ISOLATION UNITS AT THE WISCONSIN CORRECTIONAL INSTITUTION. THE REFERENCE GROUP INCLUDED 90 MEN AND THE TREATMENT GROUP CONSISTED OF 87 MEN. BEHAVIORAL PROBLEMS EXHIBITED BY EACH GROUP WERE EXAMINED THROUGH COMPARISONS OF THE NUMBER OF CONDUCT VIOLATIONS RECEIVED BY THE MEMBERS OF THE GROUP DURING A 6-MONTH TIME PERIOD. IT WAS FOUND THAT NO SIGNIFICANT DIFFERENCES EXISTED BETWEEN THE REFERENCE GROUP AND THE TREATMENT GROUP IN RELATIVE FREQUENCIES OF AGGRESSIVE BEHAVIOR, DRUG-RELATED BEHAVIOR, SEXUALLY DEVIANT BEHAVIOR, AND POSSESSION OF CONTRABAND MATERIALS. IT WAS DISCOVERED, HOWEVER, THAT THE TREATMENT GROUP SHOWED SIGNIFICANTLY HIGHER FREQUENCIES OF RULE VIOLATIONS AND RECIDIVISM FOR THE FIRST 3 MONTHS OF THE STUDY PERIOD. AMONG THE REASONS CITED FOR THE POOR BEHAVIORAL ADJUSTMENT OF THE TREATMENT GROUP WERE: THE CORRECTIONAL ENVIRONMENT, AND ESPECIALLY THE MAXIMUM-SECURITY ENVIRONMENT, IS NOT CONDUCIVE TO TREATMENT; INMATES WHO ARE IN ISOLATION SEEM TO HAVE MORE DIFFICULTY THAN USUAL IN DEALING WITH AUTHORITY; THE 'OPEN-ENDED' STRUCTURE OF THE GROUPS SEEMS TO HAVE FUNCTIONED AS A NEGATIVE FACTOR IN THAT IT REDUCED FEELINGS OF COHESIVENESS AMONG GROUP MEMBERS; AND THERE WAS NO SELECTION PROCEDURE THAT COULD BE USED TO SCREEN OUT SUBJECTS NOT AMENABLE TO TREATMENT. IT IS SUGGESTED THAT FUTURE GROUPS WOULD BE MORE SUCCESSFUL IF THEY OPERATED AS SELECTIVE, PARTIALLY OPEN-ENDED GROUPS. IT IS ALSO RECOMMENDED THAT LONG-TERM OR 'REPEATER' OFFENDERS WHO ARE KNOWN TO BE ANTAGONISTIC TO INSTITUTIONAL CONTROLS, PROGRAMS, OR AUTHORITY SHOULD BE TRANSFERRED TO SPECIAL INTENSIVE TREATMENT PROGRAMS OUTSIDE THE CORRECTIONAL INSTITUTION.