Modeling Physical Accessibility to Health Care and Geographic Coverage (AccessMod©)
Service provision (availability and quality of care) and coverage of interventions are respectively a key function and goal of an overall health system. They have a direct impact on health outcomes and therefore on the burden of disease that affects many countries in the developing world.
In this context, being able to measure effective coverage, defined as the probability that an individual will receive health gain from an intervention if they need it, contributes to a wider understanding of the performance of health systems which facilitates the development of evidence based health policies.
Two of the components defining effective coverage do actually have a geographic dimension: availability and accessibility coverage.
Availability coverage reflects what resources are available and in what amount for delivering an intervention. This may include the number of health facilities, number of personnel, hours of operation, waiting time or the availability of different technologies (drugs, etc…). Accessibility coverage measures how physically accessible resources are for the population. The resources might be available but inconveniently located, therefore hindering physical access.
The independent analysis of these two components only provide uni-dimensional perspectives as the first one informs us about the availability of a service without considering if the population can actually physically access it while the second one tell us if the point of care can easily be accessed but without considering if the supply of care is sufficient to cover the demand.
Combining both is not easy because it requires taking into account conjointly the location and the maximum coverage capacity of each care provider, the geographic distribution of the population, the environment that the patient will have to cross to reach the care provider, as well as the transportation mode s/he will be using.
As this is possible within a GIS, AccessMod© has been developed to take advantage of this capacity and therefore provide Ministries of health with a set of tools to measure both physical accessibility as well as this combined measure referred to as geographic coverage.