Assessing Clinically Significant Change: Application to the SCL-90–R

A Symptom Checklist (SCL-90-R) is a potentially useful measure of psychological distress; it is frequently used in psychotherapy research and clinical practice. The purpose of this study was to illustrate the use of the SCL-90-R for determining statistically reliable change and clinical significance outlined by Jacobson and Truax in 1991. This paper describes the concepts of statistical and clinical significance of change. A proposal for obtaining and characterizing samples is made. Then a clinician's perspective is taken. Reliable change estimates and cut-off scores are chosen based on outcome data. Selected data from a single psychotherapeutic process and outcome study then were used to test the estimates of change and cut-off scores.