Calculating clinically significant change: Applications of the Clinical Global Impressions (CGI) Scale to evaluate client outcomes in private practice

The Clinical Global Impressions (CGI) scale is a therapist-rated measure of client outcome that has been widely used within the research literature. The current study aimed to develop reliable and clinically significant change indices for the CGI, and to demonstrate its application in private psychological practice. Following the guidelines developed by Clement, a file review was conducted of the authors’ first six years working in private practice. A reliable change on the CGI required the participants score to change by 2-points. Depending on the method used to calculate the clinical change indices, between 23% and 50% of the total participants demonstrated reliable and clinical significant improvement. The CGI proved to be a useful tool to retrospectively evaluate clinical outcomes in private practice.