The Social Geography of American Medicine

Health care exhibits wide geographic variation. Because care is driven by the behavior of physicians, regional differences in its cost and quality are thought to reflect local cultures of medical practice, but the mechanisms producing and maintaining these putative cultures remain unclear. Local billing and prescribing cultures may be reflected in physician referral networks, but the complexity of U.S. health care has made it difficult to study such networks on a nationwide basis. Here we combine comprehensive, longitudinal, publicly available data on physician billing, prescribing, and patient-sharing behavior to characterize the “social geography” underlying area variations in health care. Focusing on six measures of billing and prescribing intensity, we investigate the clustering of physicians’ behavior on the basis of their social proximity in patient-sharing networks, finding that both social influence and selection contribute to the clustering observed. Our results have implications for efforts to improve the value and quality of health care, and highlight the potential of publicly available administrative data in promoting transparency in research and public affairs