medical providers to store and exchange patient information using computers rather than paper records. Hospitals may not adopt … adoption if hospitals cannot benefit from exchanging patient information with one another. In the US, medical privacy laws that … restrict the ability of hospitals to disclose patient information vary across time and across states. We exploit this variation …

hospitals in larger hospital systems are more likely to exchange electronic patient information only within their system and … less likely to exchange patient information externally. We show that hospitals are also more likely to exchange information … externally if others hospitals also do so. This implies that the disinclination of large hospital systems to exchange data …