Limitations of the Dodo bird verdict and the role of clinical trials in psychotherapy research: Comment

B. E. Wampold et al.'s (1997) meta-analysis provides a useful and methodologically sophisticated summary of the results of comparative psychotherapy outcome research. Despite its strengths, some limitations of the meta-analysis that may have biased the results against finding differences between treatments are pointed out in this article. in addition. the types of treatments and patient populations to which the results can be generalized are clarified through an analysis of the studies contained within the meta-analysis, The importance of exceptions to the Dodo bird verdict is emphasized. Disagreements with Wampold et al. on the implications of the their meta-analysis for research and practice, in particular the role of clinical trials in psychotherapy research and the need for identifying treatments that are ''empirically supported,'' are discussed.