Welcome to the party, but...

Laska, Gurman, and Wampold (2014, pp. 467-481) argue for the inclusion of common factors (CF) approaches to psychotherapy to be an alternative to empirically supported therapies when developing an evidence-based practice. Although we applaud their scholarship and the cogency of their arguments, we believe that they fall short of what is needed to define an optimal and effective therapy. Integration rather than amalgamation better captures the complexity of psychotherapy and adds to the explained variance. While CF dimensions certainly should be considered within the research definition of "psychotherapy," there are also important characteristics of the participants that are not captured in either the patient's diagnosis or the interventions that the therapist uses that affect outcome. We believe that the authors have inadvertently equated CFs with nonspecific ones and thus excluded a host of moderating variables in psychotherapy that produce specific and differential effects but which are not "nonspecific".