Border crossing for physician services: implications for controlling expenditures.

In this article, the authors explore geographic border crossing for the use of Medicare physician services. Using data from the 1988 Part B Medicare Annual Data (BMAD) file, they find that there is substantial geographic variation across both States and urban and rural areas in border crossing to seek services. As might be expected, there is more border crossing among smaller geographic areas than among States. Predominantly rural areas tend to be major importers of services, but urban areas, on average, export services. Border crossing tends to be greater for high-technology services such as advanced imaging, cardiovascular surgery, and oncology procedures. These results suggest that expenditure-control policies applying to States or metropolitan areas should incorporate adjusters for patients' current geographic patterns of care.