This study evaluates 3 drug-testing strategies implemented in 5 different jurisdictions with drug courts in Orange County, California. The purpose of the study was to determine whether the sweat patch acts as a deterrent and under what conditions it can be used to improve outcomes. Results indicated that although the use of the sweat patch did not result in statistically significant higher retention or graduation rates, it was perceived to be equal to the use of urine analysis in deterrent effect. The effectiveness of testing as a deterrent for drug use will likely depend on the scheduled administration of the tests and the immediacy of rewards and sanctions for participants. (Contains 1 table and 1 figure.)