The analyses used similar time periods and methodologies. The research focused on what happens to former clients after they leave drug treatment and whether differing outcomes are associated with different treatment techniques. Data came from random samples of clients provided various treatment approaches, including methadone maintenance, outpatient, residential therapeutic community, and detoxification. Outcomes were measured in terms of drug use, employment status, and criminal activity as indicated by arrests and incarcerations. Both studies examined client behavior during the 2-month period before entry into drug treatment, the 2-month period after treatment, and the 2-month period before the followup interview. Results revealed a relatively high rate of prosocial behavioral change, almost independently of the type of treatment initiated or whether the client remained in treatment for more than brief periods. In addition, demographic and background factors failed to explain success or failure in treatment. Footnotes and appended tables