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 (eg, 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.