This data collection represents a combined experimental evaluation of a drug court program, implemented in 1992 in cooperation with the Maricopa County Adult Probation Department, in comparison to standard probation with different levels of drug testing. The experiment's objective was to compare the drug use and criminal behavior of probationers assigned to four alternative regimes or tracks: (1) standard probation, but no drug testing, (2) standard probation with random monthly drug tests, (3) standard probation with testing scheduled twice a week, and (4) drug court, an integrated program of drug testing, treatment, and sanctions that utilized a carefully structured set of rewards and punishments. The experiment was limited to first-time felony offenders convicted of drug possession or use (not sales) and sentenced to a term of three years' probation. A total of 630 probationers from Maricopa County were randomly assigned to one of the four experimental regimes and tracked for a 12-month period. Data collection efforts included: (1) background information on each participant, (2) process information on the characteristics of supervision and services provided under each experimental condition, and (3) follow-up data on subsequent drug use, crime, and pro-social activities for 12 full months. Background Data (Part 1) include demographic variables such as race, sex, education, marital status, living arrangements, and employment history. In addition, there are variables on prior drug use and abuse, drug treatment, criminal histories as both a juvenile and an adult, and risk and need assessment scores. Other variables include the results of drug testing and any sanctions taken for a positive result (Part 2), new arrests while on probation and corresponding disposition and conviction (Part 3), and technical violations and any actions taken for these violations (Part 4). For probationers assigned to drug court (Part 5) there are variables measuring probationers' status, probation recommendations, and judges' decisions at 11 different progress assessments. The follow-up information (Parts 6-8) includes monthly data on the status of the probationer, the number of face-to-face office contacts, phone contacts, work/school contacts, and community contacts, collateral checks, employment/school verification, counseling sessions, alcohol tests, drug tests, substance abuse treatment, the number of hours the probationer spent job hunting, in educational training, in vocational training, and in community service, the number of days employed full- and part-time, and the amount of earnings, fines paid, restitution paid, and fees paid.