Table 2.

Summary of common methodologies for the synthesis of qualitative health research*

Methodology	Critical interpretive synthesis	Grounded theory synthesis	Meta-ethnography	Meta-study	Thematic synthesis
Key seminal methodology references	Dixon-woods et al. 2006 [4]	Kearney 2001 [23], Eaves 2001 [22]	Noblit and Hare 1988 [11], Britten et al. 2002 [2]	Paterson et al. 2001 [24]	Thomas and Harden 2008 [12]
Philosophical positioning**	Subjective idealism – no single shared reality independent of multiple alterative human constructions	Objective idealism – a world of collectively shared understandings exists	Objective idealism – a world of collectively shared understandings exists	Subjective idealism – no single shared reality independent of multiple alterative human constructions	Critical realism – knowledge of reality is medicated by one’s beliefs and perspectives
Literature search	Theoretical sampling	Theoretical sampling	Non-specified	Not-specified	Systematic, comprehensive
Quality appraisal	The degree to which the research findings can inform theory development	Implicit judgement about the context, quality and usefulness of the study	Judgement based on relevance; CASP	Focuses on rigour and the epistemological soundness of the research methods	Criteria related to aims, context, rationale, methods and findings, reliability, validity, appropriateness of methods for ensuring findings are grounded in participant perspectives
Analysis techniques and concepts	· Concurrent iteration of the research questions	· Concurrent data collection and analysis	· Reciprocal translational analysis (translation of concepts from individual studies – 1st/2nd order constructs)	· Analyse findings – meta-data-analysis	· Line by line coding of text from primary studies
	· Extract data and summarise papers	· Theory is derived inductively from the data	· Refutational synthesis (explore and explain contradictions between studies – 1st/2nd order constructs)	· Analyse methods – meta-method)	· Free codes organised into descriptive themes
	· Define and apply codes	· Constant comparison of data	· Lines of argument (grounded theorising based on synthesising translations)	· Analyse theory – meta-theory	· Further interpretation to develop analytical themes
	· Develop a critique, generate themes			· Bring together all three components of the analysis
Synthesis output	· New theoretical conceptualisation – synthetic construct	· Generation of a new, higher-level grounded theory	· New insights – 3rd order constructs	· Account for differences in research findings	· Analytical themes that offer a new interpretation that goes beyond the primary studies
				· New interpretation of phenomena studied
Topic areas and study references†	Access to healthcare by vulnerable groups [4], pain management [26]	Domestic violence [23], caregiving [22]	Medicine-taking [3], patients’ help-seeking experiences in cancer presentation [6], palliative care [27]	Chronic illness experience [14], influences on shared decisions making [15], adolescent health [16]	Children’s experiences of health eating [12], chronic kidney disease [28], people’s understanding of cancer risk [29], organ transplantation [7], patient-physician relationships [30]

*This is not a complete list of methodologies as methodologies for the synthesis of qualitative health research are wide ranging; **Adapted from Barnett-Page and Thomas [1] and Spencer et al. [31]. ^†References selected to reflect a range of topic areas in health research.