Realist synthesis: an introduction

This guide, written by Ray Pawson, Trisha Greenhalgh, Gill Harvey and Kieran Walshe for the ESRC Research Methods Programme, provides an introduction to using realist synthesis, with a focus on health service reforms in the UK. The paper guides the reader through understanding the principles of realist synthesis, the steps to undertaking a realist review and the applications, scope and limitations of the realist approach.


"Realist review is a relatively new strategy for synthesising research, which has an explanatory rather than judgemental focus. Specifically, it seeks to ‘unpack the mechanism’ of how complex programmes work (or why they fail) in particular contexts and settings. Realism has roots in philosophy, the social sciences, and evaluation, but is as yet largely untried as an approach to the synthesis of evidence in healthcare and other policy arenas in which programmes are delivered through an intricate institutional apparatus. We believe that it fills an important methodological need, long identified by heath service decision makers, for a synthesis method that can cope effectively with management and service delivery interventions. Compared to clinical treatments, which are conceptually simple and have been evaluated in randomised controlled trials, the literature on service interventions is epistemologically complex and methodologically diverse. As such, it presents additional challenges for the reviewer. The time is long overdue for developing distinct ways of drawing the evidence together." (Pawson, Greenhalgh, Harvey and Walshe, 2004)


  • Part I: The principles of realist enquiry 2
    • The ‘realist’ perspective 2
    • The nature of interventions 4
    • Realist review and complex policy interventions 11
  • Part II: Practical steps in realist review 13
    • Rethinking the standard template 13
    • Clarifying the scope of the review 13
    • Searching for relevant evidence 19
    • Appraising the quality of evidence 21
    • Extracting the data 23
    • Synthesising the evidence 24
    • Drawing conclusions, framing recommendations and disseminating findings 26
    • The realist template for systematic review 28
  • Part III: Applications, scope and limitations 30
    • Realist reviews and policymaking 30
    • Realist reviews and the wider evidence base 31
    • Strengths and limitations of the realist approach 37
    • Relationship with other forms of synthesis 40


Pawson, R., Greenhalgh, T., Harvey, G., and Walshe, K., (2004). Realist synthesis:  an introduction,  ESRC Research Methods Programme, University of Manchester. Retrieved from:

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