Like many areas of healthcare practice and policy, the literature on access to healthcare is large, diverse, and complex. It includes empirical work using both qualitative and quantitative methods; editorial comment and theoretical work; case studies; evaluative, epidemiological, trial, descriptive, sociological, psychological, management, and economics papers, as well as policy documents and political statements. "Access" itself has not been consistently defined or operationalised across the field. There are substantial adjunct literatures, including those on quality in healthcare, priority-setting, and patient satisfaction. A review of the area would be of most benefit if it were to produce a "mid-range" theoretical account of the evidence and existing theory that is neither so abstract that it lacks empirical applicability nor so specific that its explanatory scope is limited.

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