Common factors: post hoc explanation or empirically based therapy approach?

Laska, Gurman, and Wampold (2014, pp. 467-481) seek to expand the lens of evidence-based practice by incorporating the common factors perspective. We comment on Laska et al.'s arguments along with the methods used to reach their conclusions. Although we share their view that the common factors explanation for therapeutic equivalence across various orientations observed in the treatment outcome literature is both parsimonious and supported by the scientific evidence, we take issue with their suggestion that there exists a common factors "approach" to treatment in general or evidence-based practice more specifically. We provide clarification and friendly amendments to their language and perspective on the psychotherapy process and outcome research literature and its application in evidence-based practice.