The study found that officers in the experimental group used the strategies they were taught more often than control officers in their interaction with clients. Also, clients supervised by officers in the experimental group had far superior outcomes compared to clients of officers in the control group, even after controlling for individual client characteristics; however, a sub-analysis found that the effects of the experimental condition were not present for high-risk clients. Officers in the experimental group were trained in the STARR program (Staff Training Aimed at Reducing Re-arrest). This involved participation in a 31/2-day training program that included a discussion of the theory underlying the STARR curriculum, a demonstration of each skill, exercises, and an opportunity for officers to practice each skill and receive feedback. The STARR skills include strategies for Active Listening; Role Clarification; Effective Use of Authority; Effective Disapproval; Effective Reinforcement; Effective Punishment; Problem Solving; and Teaching, Applying, and Reviewing the Cognitive Model. Officers in the control group did not receive the training. Officers' use of the skills taught was measured by reviewing audio-tape recordings of interactions with clients recruited for the study. Pretrial client outcomes were measured by failure to appear in court, supervision being revoked, or being arrested for a new criminal charge. Outcomes for clients on post-conviction supervision were measured by re-arrest for a new offense within 12 months. 9 tables, 1 figure, and 25 references