Formalised research synthesis to underpin evidence-based policy and practice has become increasingly important in areas of public policy. In this paper we discuss whether the Cochrane standard for systematic reviews of healthcare interventions is appropriate for social research. We examine the formal criteria of the Cochrane Collaboration for including particular study designs and search the Cochrane Library to provide quantitative evidence on the de facto standard of actual Cochrane reviews. By identifying the sample of Cochrane reviews that consider observational designs, we are able to conclude that the majority of reviews appears limited to considering randomised controlled trials only. Because recent studies have delineated conditions for observational studies in social research to produce valid evidence, we argue that an inclusive approach is essential for truly evidence-based policy and practice in regard to social interventions.