The health care system in the United States has experienced drastic changes in the recent past. Continuously growing pressures to control health care costs and the increasing corporatization of health care are changing physician decisions about how and where to provide medical care. Physicians are increasingly drawn to medical office complexes, group practices, and hospital-owned practices, resulting in a shifting landscape of physician services. The goal of this research is to analyze the changing spatial distribution and clustering of primary care physicians in Cook County, Illinois from 2000 to 2008. Using data from the American Medical Association's Physicians Master File for 2000 and 2008, primary care physician locations are geocoded, mapped, and analyzed to evaluate change over time. Spatial analysis methods such as kernel density mapping and the L-function are used to analyze changes in the spatial clustering and dispersion of primary care physician locations. Geographically weighted regression models are then used to compare primary care physician supply to the socioeconomic demographics of census tracts in Cook County. Results indicate that spatial clustering of primary care physicians increased over the eight year period. Linear regression analyses show positive relationships between primary care physician-to-population ratios and median income and percentage of the work force employed. However, geographically weighted regression shows that these relationships vary throughout the county. Implications for access to care and possible policy changes to increase primary care physician spatial accessibility are discussed
