Using an independent cognitive-behavioral therapy (CBT) data set, the authors replicated T. Z. Tang and R. J. DeRubeis' (1999) discovery of sudden gains--sudden and large decreases in depression severity in a single between-session interval. By incorporating therapy session transcripts, the authors of this study improved the reliability of the Patient Cognitive Change Scale to .75 and found that these CBT sudden gains were also preceded by substantial cognitive changes in the pregain sessions.