The application of statistical process control to manage global client outcomes in behavioral healthcare

Statistical process control (SPC) techniques were applied to simulate monitoring the process of outpatient service delivery at two menial health centers using data collected 23 years earlier. Clients included in this study received between two and 21 psychotherapy visits during the previously conducted evaluation study. Global outcomes for clients were derived from weekly ratings of functioning provided by the client and therapist. The self-report and therapist ratings were aggregated, then combined across visits to estimate the rate of linear change in functioning. Rates of change were plotted in a control chart format, using the moving average of two scores to estimate the range. Special causes of high variability and a downward trend were noted for all discharges at both centers. Control limits were re-estimated for the discharges following the downward trend in scores. Subsequently, the service processes supporting global client outcomes no longer varied uncontrollably. However, upon estimating specification limits for global client outcomes, it was noted that the mean level of client outcome fell below the mean specified as the target and that some discharges yielded unacceptable outcomes. (C) 1999 Elsevier Science Ltd. All rights reserved.