In a 2003 report, New York's Center for Court Innovation compared recidivism rates between drug court graduates and attendees from six different drug courts, and control groups of similar defendants not entering drug court. They found that "When in-program participation time was included in the calculation, processing time for participants was far longer than for comparison defendants (due to the length of the drug court program). Hence to achieve positive impacts such as lower recidivism, drug courts require a significant up-front investment of court resources."

Source

Rempel, Michael, Dana Fox-Kralstein, Amanda Cissner, Robyn Cohen, Melissa Labriola, Donald Farole, Ann Bader and Michael Magnani, "The New York State Adult Drug Court Evaluation: Policies, Participants and Impacts" (New York, NY: Center for Court Innovation, Oct. 2003), p. xi.
http://www.courtinnovation.or…