"With regard to drug courts’ effectiveness, however, drug courts have been difficult to evaluate because they are so varied, and the resources required to conduct a study that would allow conclusions about the effectiveness of drug courts can be substantial. In particular, while drug courts generally adhere to certain key program components, drug courts can differ in factors including admission criteria, type and duration of drug treatment, degree of judicial monitoring and intervention, and application of sanctions for noncompliance. In February 2005, we studied drug courts and reported that in most of the 27 drug-court program evaluations we reviewed, adult drug court programs led to recidivism reductions during periods of time that generally corresponded to the length of the drug court program.19 Several syntheses of multiple drug court program evaluations, conducted in 2005 and 2006, also concluded that drug courts are associated with reduced recidivism rates, compared to traditional correctional options. However, the studies included in these syntheses often had methodological limitations, such as the lack of equivalent comparison groups and the lack of appropriate statistical controls.20"
"Adult Drug Courts: Studies Show Courts Reduce Recidivism, but DOJ Could Enhance Future Performance Measure Revision Efforts" (Washington, DC: Government Accountability Office, Dec. 2011), GAO-12-53, pp. 8-9.