Formal qualitative synthesis is the process of pooling qualitative and mixed-method research data, and then drawing conclusions regarding the collective meaning of the research. Qualitative synthesis is regularly used within systematic reviews in the health professions literature, although such use has been heavily debated in the general literature. This controversy arises in part from the inherent tensions found when generalisations are derived from in-depth studies that are heavily context-dependent. We explore three representative qualitative synthesis methodologies: thematic analysis; meta-ethnography, and realist synthesis. These can be understood across two dimensions: integrative to interpretative, and idealist to realist. Three examples are used to illustrate the relative strengths and limitations of these approaches. Against a backdrop of controversy and diverse methodologies, readers must take a critical stand when reading literature reviews that use qualitative synthesis to derive their findings. We argue that notions of qualitative rigour such as transparency and acknowledgment of the researchers' stance should be applied to qualitative synthesis. © Blackwell Publishing Ltd 2013.
