Methods for the thematic synthesis of qualitative research in systematic reviews

There is a growing recognition of the value of synthesising qualitative research in the evidence base in order to facilitate effective and appropriate policy and practice. In response to this, methods for undertaking these syntheses are currently being developed. Thematic analysis is a method that is often used to analyse data in primary qualitative research. This paper reports on the use of this type of analysis in systematic reviews to bring together and integrate the findings of multiple qualitative studies. We describe the activity of thematic synthesis, outline several steps for its conduct and illustrate the process and outcome of this approach using a completed review of health promotion and public health research. We compare thematic synthesis to other methods for the synthesis of qualitative research and discuss issues of context and rigour.