Social networks, information and health care utilization: evidence from undocumented immigrants in Milan.

This paper uses a novel dataset and research design to examine the effects of information networks on immigrants' access to health care. The dataset consists of an unusually large sample of undocumented immigrants and contains a direct indicator of information networks-whether an immigrant was referred to health care opportunities by a strong social tie (relative or friend). This measure allows to overcome some of the major identification issues that afflict most of the existing literature on network effects and to concentrate on one of the channels through which social contacts might operate. The analysis focuses on the time spent in Italy before an immigrant first receives medical assistance. Estimates indicate that networks significantly foster health care utilization: after controlling for all available individual characteristics and for ethnic heterogeneity, I find that relying on a strong social tie reduces the time to visit by 30%. The effect of information networks is stable across specifications and it is relatively large. Further investigation seems to confirm the quantitative importance of networks as an information device.