Physicians, both directly through services they provide and indirectly through the services that they order, shape the vast majority of health care utilization in the US. There has long been interest in the determinants of physician decision making because optimizing physician decisions has the potential to improve the quality of US health care while also controlling costs by eliminating the use of unnecessary services.

One influence on physician decision-making that has largely been ignored derives from the influence of networks of physicians on individual physician decision making. In this setting, “networks” refer to informal networks of primary care and specialist physicians who share patients and information, rather than to formal networks of all of the physicians formally affiliated with a health plan or hospital. In practice, each physician, particularly each primary care physician, develops distinct sets of specialist physicians with whom they share patients and information. By virtue of sharing patients, these networks can be defined empirically.  These networks of physicians have the potential to influence an individual physician’s decision making, and such influences may vary depending on the structure of the network and/or occurrences within the network.

Physician networks and their influence on physician decision-making, however, have rarely been studied. In this project, we aim to improve our understanding of the influence of physician networks on physician decision-making using national data from the Medicare program. We also aim to explore the contribution of network properties to observed variations in spending and treatment patterns within the Medicare program.

The role of networks and the extent to which network connections influence the clinical decisions made by individual physicians is unknown.  A better understanding of this complex phenomenon will provide novel insights into the role that provider connections play in the delivery of health care.