1/ What new dimensions do you use to define and measure accessibility to general practitioners?

Research on spatial inequalities of accessibility to primary care, based on "floating density " type indicators or Two-Step Floating Catchment Area (2SFCA), has made it possible in recent years to go beyond the limits of traditional indicators of density and distance. Adapted to the French context, the Local Potential Accessibility (LPA) makes it possible to reconsider the observations previously made in this area by proposing methodological advances but also better quantification of the healthcare supply and needs and an adjusted understanding of the interaction between supply and demand. To further improve the measurement, we are developing this indicator in several ways thanks to new voluminous databases: by reducing the geographical scale of observation, from the municipality to the 200 x 200m grid; by taking into account the social dimension of needs and differentiated mobility practices (car, public transport, etc.); by considering the systemic effect of interactions between supply and demand on a regional scale; by taking into account the specialist care supply.

2/ Why focus on the Ile-de-France region?

We focus on this region in order to take into account the specificities of a multipolarised and socially and morphologically diverse region. Indeed, it is a region with an exceptionally dense conurbation core and a very well-serviced public transport network. It is, at the same time, a region with a large area of peri-urban and rural areas in the outer suburbs, where the problems of accessibility to care are quite different.
Moreover, by restricting ourselves to the study of a single region, we have more detailed data (travel times matrices from grid to grid by car, walking and public transport), we have been able to geolocate all the health professionals at the address and then at the grid... Restricting ourselves to a single region finally makes it possible to limit the volume of data mobilised and to reduce the calculation times to reasonable durations.

3/ What are the results of the different scenarios you propose?

The results are presented in the form of scenarios comparing the effect of each of the hypotheses introduced. The change in the geographical scale of observation highlights situations that are sometimes very contrasting between different districts in the same municipality. Taking into account the interactions between healthcare supply and demand on a regional scale is the second evolution that most affects the measured levels of accessibility, "smoothing" the spatial representation of accessibility levels by rebalancing the situations between neighbouring grids. The integration of the social dimension of differentiated mobility needs and practices (car, public transport...) has more local impacts. For example, weighting populations according to age increases needs in the departments of Paris and Hauts-de-Seine mainly, while the introduction of the social dimension of needs has a particularly significant impact in Seine-Saint-Denis. Finally, putting the indicator into a more global context, particularly by taking into account alternative medical supply in primary care specialists, leads to a very significantly modified vision of infra-regional balances.

Interview by Anna Marek