Table 2.

Application of the framework synthesis method

Framework synthesis stage	Synthesis steps	Application in this review
Stage 1 Developing an initial conceptual framework	1.Familiarization: Becoming immersed in the data	Undertaken during full-text screening and study selection (both stages), in addition to reading quantitative literature, systematic and narrative reviews for the field, handsearching references
	2.Framework selection: Identification of key themes to inform the framework	Systematic extraction of salient themes and findings from 18 studies identified in Step 1, identification of relevant theory and definitions (see Additional file 3 for full description)
Stage 2 Recognising patterns of data through an iterative process of aggregation and configuration	3.Indexing: Systematically tagging and labelling key themes in the data	Data extracted, labelled, and indexed in NVivo software, using codebook developed from initial conceptual framework. Data not fitting framework analysed inductively
	4.Charting: Devising a series of thematic charts to allow the full pattern across papers to be explored and reviewed	Themes developed and revised iteratively in NVivo. Findings/ themes charted in Excel, patterns across data and studies explored
	5.Mapping and interpretation: Drawing together the synthesis, consideration of how the themes answer the review question	Conceptual framework developed further to reflect review findings. Relationships between themes mapped and illustrated in Figures using PowerPoint

The ‘Framework synthesis stage’ and ‘Synthesis steps’ columns are informed by the work of Brunton et al. [72] and Gough et al. [73].