This study examined data collected on over 5,000 clients seen by 71 therapists over a 6-year period in a University Counseling Center. Clients were given the Outcome Questionnaire-45 (OQ-45) on a session-by-session basis to track their treatment response. Data were also collected on therapists' theoretical orientation, years of experience, gender, and type of training. Data were analyzed using hierarchical linear modeling (HLM) to see if general therapist traits (i.e., theoretical orientation, type of training) accounted for differences in clients' rate of improvement. Data were then analyzed, again using HLM with therapists as a fixed effect, to compare individual therapists to see if there were significant differences in the efficiency of treatment. In addition, pre- minus posttest OQ-45 scores were examined to see if there were differences in the overall outcome of clients. There was a significant amount of variation among therapists' clients' rates of improvement. Therapist feedback reports were generated to summarize client outcome for individual providers in contrast to center averages and in an attempt to improve client outcome. © 2006 Wiley Periodicals, Inc. J Clin Psychol 62: 1157–1172, 2006.