The geography of hospital admission in a National Health Service with patient choice: evidence from Italy.

It is evaluated that, each year, 35% out of the 10 million hospital admissions in Italy take place outside the LHAs of residence. In our paper we try to give an explanation of this phenomenon making reference to the social gravity model of spatial interaction. We estimate gravity equations using a Poisson pseudo maximum likelihood method, as proposed by Santos-Silva and Tenreyro (2006). Our results suggest that the gravity model is a good framework for explaining the patient mobility phenomenon for most of the examined diagnostic groups. Our evidence suggests that the ability to contain the imports of hospital services increases with the size of the pool of enrolees. Moreover we find that the ability to export hospital services, as proxied by the ratio of export-to-internal demand, is U-shaped. Therefore our evidence suggests that there are scale effect played by the size of the pool of enrolees.