	Introduction

An adequate physician supply is important for the effective and efficient delivery of health care services and, therefore, for population health and the cost and quality of health care. Assessments of the adequacy of physician supply often focus on three dimensions of the physician population: its size; its composition (e.g., the distribution of primary care and specialty physicians); and its geographic distribution. Policies that aim to alter physician supply generally focus on both current and future supply along these three dimensions because physician training is a lengthy process; therefore, changes implemented to alter supply do not have immediate effects. Each of the three dimensions of physician supply is important for health care spending because physician clinical decisions affect approximately 90% of each health care dollar spent. The size of the physician population partially determines the volume of health services provided and therefore costs, as physicians provide health care services that generally cannot be provided by non-physicians. The composition of the physician population also affects population health. The federal government supports physician services and training, which may make the adequacy of the current and future physician supply of interest to Congress. Specifically, the federal government pays for physician services, primarily through the Medicare and Medicaid programs. The federal government also supports physician training through a number of programs in various departments and agencies. On March 23, 2010, President Obama signed the Patient Protection and Affordable Care Act (ACA, P.L. This report examines each dimension of physician supply, separately discussing current (and, where appropriate, future) concerns and changes included in the ACA that may affect each dimension. The report then discusses workforce planning activities included in the ACA that may affect all of these dimensions of supply. ACA and the Size of the Physician Population

The ACA may affect both the demand for physician services as well as the volume of physician services available, and therefore may influence determinations of the appropriate size of the physician population. ACA and the Geographic Distribution of the Physician Population

The ACA includes provisions that may expand the number of NHSC providers available to serve in shortage areas, increase the diversity of the physician workforce, and increase physician training in shortage areas. The ACA may intensify some of these concerns; specifically, although the ACA includes a number of provisions that aim to alter physician supply, it is not yet known whether and how these provisions will affect physician supply. Many of the programs established by the ACA have not yet been implemented, and others may not have immediate effects. In addition, some the ACA programs are temporary, and many rely on discretionary funding.
An adequate physician supply is important for the effective and efficient delivery of health care services and, therefore, for population health and the cost and quality of health care. Assessments of the adequacy of physician supply often focus on three dimensions of the physician population: its size; its composition (e.g., the mix between primary care and specialty physicians); and its geographic distribution. Policies that aim to alter physician supply generally focus on both current and future supply along these three dimensions because physician training is a lengthy process; therefore, changes implemented to alter supply do not have immediate effects.
Each of the three dimensions of physician supply is important for health care spending and for population health because physician clinical decisions affect approximately 90% of each health care dollar spent. In addition, as physicians provide health care services that, with some exceptions, cannot be provided by non-physicians, the size, composition, and geographic distribution of the physician population affects the amount and type of health care services available. A number of studies have found physician shortages overall, in certain specialties, and in certain geographic areas. The federal government pays for physician services, primarily through the Medicare and Medicaid programs, and supports physician training through a number of programs in various departments and agencies. Given current investments in physician services and the physician workforce, the adequacy of the current and future physician supply may be of interest to Congress.
The Patient Protection and Affordable Care Act (ACA, P.L. 111-148, as amended) may affect the demand for physician services, a major determinant of physician supply, because it expands insurance coverage to some of those previously uninsured. The ACA also includes provisions that may affect the size, composition, and geographic distribution of the physician population by supporting changes to physician training, compensation, and practice. Specifically, provisions targeting the number of physicians trained and their productivity may affect the size of the physician population. The composition of the physician population may be altered by provisions targeting the supply of primary care providers or specialties in shortage. Provisions addressing the diversity of the physician workforce and those incentivizing practice in rural or other underserved areas may affect the geographic distribution of the physician population. Finally, the ACA includes provisions that provide for data collection and evaluation of the adequacy of the workforce in general, and federal workforce programs specifically. Whether and how these provisions will affect physician supply is not yet known because some of these provisions have not been implemented yet, are temporary, will not have immediate effects, or rely on discretionary funding.
This report examines each dimension of physician supply, separately discussing current (and, where appropriate, future) concerns and relevant changes included in the ACA that may affect each dimension. The report then discusses workforce planning activities included in the ACA that may affect all three dimensions of supply.