MHV3SFCA: A new measure to capture the spatial accessibility of health care systems

Good accessibility of health care services is essential to meet the needs of the population and ensure adequate health care coverage. It usually refers to two spatial dimensions: availability (competition between populations for the same medical supply) and reachability (distance between population and medical supply). Traditional indicators of health care accessibility usually fail to consider both of these components simultaneously. Floating-Catchment-Area (FCA) methods were developed to address these shortcomings. This study reviews the existing FCA methods and proposes the Modified Huff-based Variable 3 Steps Floating Catchment Area (MHV3SFCA) method as a new approach. The MHV3SFCA method integrates the strengths of several existing FCA methods into a single method, such as supply competition through the Huff model, and the integration of variable effective catchment sizes. In addition, and as a novelty, the MHV3SFCA relies on the assumption of a constant overall population demand, independent of the distances between population units and supply sites. It also accounts for absolute difference in distances without overestimating distance effects. Based on the results of a simulation study the paper discusses the strengths of the MHV3SFCA method capturing spatial differences in access to health care services.