What is the best way to measure access to primary care physicians? Michael Daly, a Research Associate at the Schroeder Center for Health Policy, recently presented preliminary findings in answer to this question to the Board of Advisors of the William & Mary Public Policy program. Daly’s presentation featured preliminary analysis using a novel geospatial measure of physician accessibility and showed that the new measure of accessibility is associated with improved ambulatory care access in Virginia. Daly is conducting this work together with researchers Marco Millones Mayer and Jennifer Mellor. Millones Mayer is a Research Fellow in Public Policy and former interim director of the College’s Center for Geospatial Analysis, and Mellor is Professor of Economics and director of William & Mary’s Schroeder Center for Health Policy.This new research uses an innovative approach to studying physician accessibility. Many previous measures assume patients see primary care physicians close to home and solely within their own geopolitical boundaries, such as counties. Often, the official primary care “shortage areas” used to allocate physician bonus payments and to determine eligibility for loan repayment programs are defined in the same way. Many times, however, patients venture outside county boundaries to seek primary care. The Schroeder Center’s study uses geospatial methods to account for these cases where patients in one area may seek care from providers in other areas. The study uses geocoded data on approximately 9,000 primary physician practice locations in Virginia. The team’s early results suggest that a geospatially-defined measure of physician accessibility may be a useful tool for policymakers when allocating resources aimed at increasing population health.