Research Articles

In describing the merits of expanding Medicaid to the uninsured, federal and state policymakers often argue that expanding Medicaid will reduce inefficient and expensive use of the emergency department (1–4). Ex-panded Medicaid coverage could, however, either increase or decrease emergency department use. On the one hand, by reducing the cost to the patient of emergency department care, expanding Medicaid could in-crease use and total health care costs. On the other hand, if Medicaid increases primary care access and use, or improves health, expanding Medicaid could reduce emergency department use, and perhaps even total health care costs. Despite the many claims made in public dis-course, existing evidence on this topic is relatively sparse, and the results are mixed. Analyses of the 2006 health insurance expansion in Massa-chusetts found either unchanged (5) or reduced (6) use of emergency departments. Quasi-experimental analysis of expanded Medicaid eligi-bility for children found no statistically significant change in emergenc