Within-Group Effect Size Benchmarks for Cognitive-Behavioral Therapy in the Treatment of Adult Depression

This article provides benchmark data on within-group effect sizes from published randomized clinical trials supporting the efficacy of cognitive-behavioral therapy (CBT) in the treatment of adult depression. Data from 84 studies that met the inclusion criteria were recorded independently by the two authors, with a 95.8% agreement rate. Aggregate within-group effect size benchmarks are provided for CBT groups and control groups and are broken down by level of depression, type of control group, type of CBT approach, type of depression measure, type of data analysis (intent-to-treat versus completers, only), and whether participants had any comorbidity. Overall, the aggregate within-group effect size estimates for CBT groups were 1.19 for self-report outcome measures and 1.52 for interviews. For control groups the estimate was 0.48 for self-reports and interviews. When treating depressed adult clients, community-based practitioners can use these benchmarks as a comparison tool to evaluate the adequacy of the way they are adopting or adapting CBT and in making decisions about whether to continue providing CBT in the same manner or to modify or replace it.