Defining and measuring unmet need to guide healthcare funding::identifying and filling the gaps.

Budget allocations to Clinical Commissioning Groups include adjustments for unmet need for healthcare, but there is a lack of robust evidence to support this. This article describes a literature review with an objective to understand the available evidence regarding unmet need. We developed a conceptual framework for what constitutes ideal evidence that; defines unmet need for a given population, indicates how that need can be met by health care, establishes the barriers to meeting need and provides relevant proxies based on observable measures. Our search focused on recent and empirical UK data and conceptual papers. We found no one article which satisfied all requirements of ideal evidence; the literature was strongest in defining need but weakest in regard to establishing observable proxies of need capable of being used in budget allocations. Our review was limited by its timescale and a vast body of literature, which translated into a limited number of key words for the search. We conclude that further research to inform budget allocation is required and should focus on conditions or services where adverse health outcomes from unmet need are amenable to healthcare interventions and which affect a sizeable proportion of the population.