Realist review Following Saul et al,26 a review group consisting of sector experts and researchers is currently being established. Identification no of articles and documents for inclusion in the review will include generating a list of relevant documents with the review group. The next step will be to undertake a rapid realist review of the literature to further map the elements of, and approaches to, health markets and trans-border patient movement, with a view to further uncovering the underlying theory. This search will be undertaken using databases such as the Ovid Medline, EMBASE, Scopus, EconLit, Web of Science and web-based searches of data available in the public domain. Combinations of key words in

English, and their truncations, will be entered in these databases;

see online supplementary file 1 for preliminary search terms. The search terms will be iteratively narrowed based on the results that are most relevant to the current review.26 The relevance of the retrieved documents will be assessed according to exclusion and inclusion criteria, and how each study clarifies the C-M-O configurations. Bibliographic references from the included documents will be reviewed, using the snowballing technique to identify additional documents as well as reference and citation tracking.13 37 We will continue to identify potential documents through this procedure throughout the review process. Only studies written in English will be included due to budgetary constraints. The search will be further limited to studies published between 2000 and 2014.

The search for new documents will end at the point of theoretical saturation—in other words, when the research yields no more sources producing new aspects of the theory. Working with the review group will help ensure that we do not omit significant sections of the literature.26 References will be compiled in EndNote. To aid in sifting documents, we will be guided by the following questions: Does the study describe a health services market? Is the study implicitly or explicitly underpinned by the theory of health services markets and demand and supply functions? Does the study provide information on demand-side and/or supply-side context of the domestic market? Does the study provide evidence GSK-3 that will contribute to the synthesis and our emerging theory? Following the RAMESES (realist and meta-narrative evidence synthesis) guidelines for realist synthesis, quality assessment will be based on how each study clarifies the C-M-O configurations.38 In realist synthesis, the criteria for quality assessment are relevance and rigour.14 Relevance refers to relevance to a specific aspect of the theory under test. Rigour relates to methodological rigour in relation to the specific finding or inference which is drawn on in the review (as opposed to the overall rigour of the whole study).