TOPS gathered longitudinal survey data on 11,000 drug abusers admitted to 41 treatment programs in 10 cities. The TOPS data were used to calculate victim costs, criminal justice costs, offenders' losses of productivity, and costs to law-abiding citizens. The analysis considers results only during the first year after discharge from treatment. Results showed that greater lengths of stay in treatment produce real returns to society and to law-abiding citizens. The benefits from each modability are at least as great as the expense. Findings showed greater economic returns from residential treatment than from methadone or outpatient drug-free treatment, but clients were not assigned randomly to the programs. Residential programs also appeared to have greater crime-reduction benefits than did the other programs. Tables and 21 references.