Improving the effects of psychotherapy has been accomplished through a variety of methods. One infrequently used method involves profiling patient outcomes within therapist in order to find the empirically supported psychotherapist. This study examined data collected on 1841 clients seen by 91 therapists over a 2.5-year period in a University Counseling Center. Clients were given the Outcome Questionnaire-45 (OQ-45) on a weekly basis. After analysing data to see if general therapist traits (i.e. theoretical orientation, type of training) accounted for differences in clients' rate of improvement, data were then analysed again using Hierarchical Linear Modeling (HLM), to compare individual therapists to see if there were significant differences in the overall outcome and speed of client improvement. There was a significant amount of variation among therapists' clients' rates of improvement. The therapists whose clients showed the fastest rate of improvement had an average rate of change 10 times greater than the mean for the sample. The therapists whose clients showed the slowest rate of improvement actually showed an average increase in symptoms among their clients. Use of this information for improving quality of patient outcomes is discussed. Copyright © 2003 John Wiley & Sons, Ltd.