Effects of geographical accessibility on the use of outpatient care services: quasi-experimental evidence from administrative panel data

Between 2008 and 2012 new outpatient service locations were established in Hungarian micro-regions, which had lacked outpatient capacities before. We exploit this quasiexperiment to estimate the effect of geographical accessibility on outpatient case numbers using both semi-aggregate and individual-level panel data from administrative sources. Based on propensity score matching methods, fixed-effect linear models and fixed-effect Poisson regression techniques, we find a substantial, 24-28 per cent increase of case numbers as a result of the establishments. Our causal estimates imply that a one-minute reduction of travel time to the nearest outpatient care provider increases case numbers e.g. by 0.8 per cent in internal medicine and 2.8 per cent in rheumatology. We also find that the size of the new outpatient capacities has a separate positive effect on case numbers, possibly caused by supplier-induced demand. By combining a fixed effect logit model and a fixed effect truncated Poisson model, we decompose the effects into increases in the probability of ever visiting a doctor on the one hand and an increase of the frequency of visits on the other. We find that new visits were the main source of the increase in internal care, surgery and gynaecology, whereas both margins wereimportant in rheumatology. Finally, as a methodological note, we examine the robustness of the fixed effect truncated Poisson estimator to some forms of misspecification by simulation methods.