How can systematic reviews incorporate qualitative research? A critical perspective

Systematic review has developed as a specific methodology for searching for, appraising and synthesizing findings of primary studies, and has rapidly become a cornerstone of the evidence-based practice and policy movement. Qualitative research has traditionally been excluded from systematic reviews, and much effort is now being invested in resolving the daunting methodological and epistemological challenges associated with trying to move towards more inclusive forms of review. We describe our experiences, as a very diverse multidisciplinary group, in attempting to incorporate qualitative research in a systematic review of support for breastfeeding. We show how every stage of the review process, from asking the review question through to searching for and sampling the evidence, appraising the evidence and producing a synthesis, provoked profound questions about whether a review that includes qualitative research can remain consistent with the frame offered by current systematic review methodology. We conclude that more debate and dialogue between the different communities that wish to develop review methodology is needed, and that attempts to impose dominant views about the appropriate means of conducting reviews of qualitative research should be resisted so that innovation can be fostered.