Lessons about patient treatment response from a large-scale outcomes management project are summarized. More than 7,000 clinicians contributed outcome data. Overall, the data demonstrated that patients who have clinical levels of psychological distress and impairment showed a relatively rapid response to treatment. Furthermore, although it appears that the duration and intensity of treatment vary widely from case to case, clinicians and patients make sound judgments as to how much and what kind of treatment is appropriate. Results supported the conclusion that the most effective method to manage costs is to ensure that each patient receive effective care. There are large and stable differences in the effectiveness of clinicians, and outcomes can be improved by referring patients to effective clinicians. The data also suggested that patients who had a poor initial response to treatment eventually had positive outcomes, provided that they remained engaged in treatment. This finding suggests that outcomes can be improved by identifying at-risk patients and proactively keeping them engaged in treatment. © 2004 Wiley Periodicals, Inc. J Clin Psychol/In Session.