tioners and then link their monitoring and punishment to treatment. Hence, after some background about probation, the evaluation research on these programs is reviewed to determine if they are effective in helping their participants to achieve abstinence.
In the past 20 years, prison populations have grown tremendously. The largest increase in the inmate population has occurred due to the rise in the number of persons incarcerated for drug possession and other nonviolent crimes related to drug use. For example, in 1980 there were 23,900 prisoners who had been incarcerated for drug use and drug sales. By 1998, that number had risen tenfold to 236,800 prisoners incarcerated for drug law violations (Blumstein and Beck, 1999; Beck, 2000). Presumably, many of these drug law violators could benefit from treatment while in prison.
A number of studies of prison-based programs seem to demonstrate positive postrelease outcomes when inmates who have gone through prison treatment programs are compared with those who have not (Wexler et al., 1992, 1996; Inciardi, 1996; Landry, 1997; Mullen, 1996; Wexler, 1996; Field, 1984). In particular, evaluations of one of the better-known prison therapeutic communities, called Stay’n Out, seem to indicate that participants in this prison treatment program experience a number of positive postrelease outcomes when they are compared with a control group that is not exposed to treatment (Wexler et al., 1992, 1996; Landry, 1997).
In an evaluation of Stay’n Out, study subjects were drawn from a waiting list of inmates who had volunteered to participate in the prison therapeutic community. These volunteers were either randomly assigned to the treatment group (who actually enrolled in the therapeutic community) or to the control group who remained on the waiting list and never received treatment. The no-treatment control group included not only those randomly assigned to the waiting list, but also those who volunteered for treatment and were not admitted because they did not have enough time left to serve to complete the 12 months recommended for prison treatment.
Because study subjects in both the treatment and no-treatment control groups volunteered for treatment, any findings from the study can be generalized only to inmates willing to volunteer for prison treatment pro-