A ccess to health care is, in part, determined by the supply of physicians available to provide treatment. Physician supply is a function of the number of physicians trained, how long they remain in practice, their productivity, and the hours they work. Policymakers have demonstrated a long-standing interest in access to care (in general and for specific populations). The federal government has identified certain health workforce concerns and creates programs that seek to address these concerns. Specifically, the Government Accountability Office (GAO) estimated that the Department of Health and Human Services (HHS) administers 72 health workforce programs. Among these programs are those that seek to increa se access to physician services, including programs that e ncourage people to enter primary care to address identified concerns that there are too few primary care physicians relative to the number of physician specialists. Federal programs also exist to recruit and retain physicians in rural areas because o f concerns that the populations that reside in these areas lack access to care. Specifically, the federal government designates some areas as medically underserved or as health professional shortage areas (HPSA) and provides benefits (e.g., higher Medicare payment rates) to providers who practice in these areas. In addition to these programs and policies, the federal government provides support for medical residency training (a.k.a., graduate medical education [GME]). Specifically, through payments that are generally made to hospitals, the federal government pays some of the costs that hospitals and other health providers incur when training residents. Such costs include, but are not limited to residents' and supervisors' salaries, and the costs of extra medical tests that residents may order as part of their training. The federal government makes a significant investment in GME—according to GAO, GME programs account for nearly three-quarters of HHS's health workforce expenditures —and GME may be a strong policy lever to impact access because the number of medical school graduates who obtain and complete a residency determines the size of the physician workforce, and the types of residencies they complete determine its specialty composition. Finally, where physicians complete their residencies often affects where they establish their practices. Given the influence of residency training on the physician population, policies that alter federal funding for GME may affect future physician supply and could be used to address identified workforce concerns. This report provides an overview of federal GME support; it discusses whether a particular source of federal GME support is actively used to further workforce goals such as altering the geographic or specialty distribution of residents trained. A number of GME critiques have raised concerns about the data that the federal government collects on these programs; for example, whether the data available are sufficient to determine program effectiveness. This report details programmatic data gaps where they have been identified. It does not summarize recent GME critiques in detail; for readers interested in such critiques, Appendix A provides some sources for further reading. Some federal programs use GME to support training for non-physician health providers; however, this report focuses only on the training of physicians. To be licensed to practice independently in a state, physicians in the United States must complete a minimum of three years of GME , with additional years required depending on their specialty. In Academic Year (AY) 2016-2017, approximately 124,000 individual residents were in training, including approximately 21,000 fellows —medical school graduates who have completed their initial residency training and are continuing their training in a fellowship in a subspecialty. (See text box for definitions.) GME generally takes place in hospitals that sponsor residency programs in specific specialties (e.g., pediatrics or surgery). Hospitals choose the number and specialties of the residents they train, but must meet accrediting body standards that attempt to assure that hospitals have the facilities, staffing, and patient load necessary to ensure that residents will receive adequate training in their chosen specialty (see text box). During their residency, residents rotate to outpatient facilities or other hospitals to gain experience treating different populations in different settings. Specific residency training requirements vary by specialty and are determined by the accrediting bodies . The federal government makes significant investments in GME funding through various programs. In FY2012, the last year of data available for all federal sources of GME payments, the federal government spent an estimated $15 billion on GME, which was the largest federal investment in the health care workforce. More recent data analyzed by GAO found that GME programs administered by the Department of Health and Human Services (HHS) and the Department of Veterans Affairs (VA) spent $14.5 billion on GME in 2015, but their work did not analyze Department of Defense GME spending. As such, 2012 remains the most recent year of a total federal GME estimate. Using their 2012 estimate, GAO found that 78% of government-wide health workforce funding was for GME; with Medicare payments accounting for 85% of this funding. Similarly, a GAO analysis of HHS programs in FY2014, found that HHS supported 72 health workforce programs, but that nearly three-quarters of all spending was from Medicare GME payments. The federal government supports GME through payments made by the Medicare and Medicaid programs, both administered by the Centers for Medicare & Medicaid Services (CMS) located in HHS; by training medical residents at Department of Veterans Affairs (VA) and Department of Defense (DOD) facilities; and by funding programs administered by HHS's Health Resources and Services Administration (HRSA) that support primary care training in outpatient facilities, rural GME program development, and training in children's hospitals. The federal government's primary role in GME has been as a payer. In this role, it has a significant influence on the physician workforce, but this role has generally been passive, because, with some exceptions, the federal government has little involvement through its support of GME in the content of training, the specialties it pays for, or training locations. In addition, the government's role in GME has generally not been linked to other federal health workforce investments, such as investments made to train non-physician providers whose work could complement or, where appropriate, replace that of physicians and who could be trained at a lower cost. These critiques have been raised particularly with regard to Medicare's GME support because it is the largest source of federal GME support, estimates of Medicare GME payments range from approximately $10.3 to $12.5 billion in FY2015. Medicare is also frequently discussed because, unlike other sources of GME support, it explicitly limits (i.e., caps) the number of residents it supports. Some argue that this limit makes increasing the number of residents and changing the locations where they train difficult. This argument generally does not take into account GME growth that occurred despite the Medicare cap. For example, recent work by GAO found that the number of residents in training grew by 22% over the 10-year period they examined (2005 to 2015), although the geographic areas where residents trained remained largely unchanged. Another analysis estimates that the number of residents in training grew by 27% during the 20-year period since the Medicare limit on GME support was enacted. This may be the case because the Medicare cap is not an absolute, and other sources—for example, other federal programs, state and local government funds, or hospital funds—can be used to expand or alter the number and types of residents in training. In addition, new hospitals can begin training residents and receive Medicare payment for doing so. Some argue that Medicare's residency limit should be partially or fully removed to address physician shortages in certain geographic areas and medical specialties. And Members of Congress have introduced legislation that would do so. Others argue that expanding Medicare support, unless done in a way that is directive; for example, by explicitly allocating positions to hospitals in specific geographic areas or requiring hospitals to fund residency positions in certain specialties, would not address identified workforce issues such as too few physicians in certain areas or practicing primary care. GAO also found that although there are incentives within Medicare and other programs to increase training in rural areas, hospitals frequently did not take advantage of them. The federal government supports workforce data collection and projections of future needs; in addition, researchers and advocates also collect and disseminate such data. Such data are necessary inputs for GME policy but are not sufficient. Determining the appropriate GME policy is inherently challenging because training a new physician is a long process; as such, attempting to change the physician workforce through changes to GME requires a long time horizon and good initial data to project the future need for physicians. This process of projection is particularly challenging because policy changes may occur in the interim that alter the assumptions used in the projections. Recent projections conducted by the National Center for Health Workforce Analysis, at HRSA, demonstrate the challenges of making projections concurrent with policy changes. In their 2013 projections, they projected that there would be a primary care physician shortage in 2020, but that the magnitude could vary greatly depending on assumptions about the role of non-physician providers. Specifically, they projected that the number of primary care physicians would grow by 8% between 2010 and 2020, but that the demand for their services would grow by 14%. They based this on the demand for services at the time of the study and assumptions about the future aging of the population, and the expected increase in insurance coverage driven by the Patient Protection and Affordable Care Act (ACA, P.L. 111-148 , as amended). These projections do not reflect more recent policy changes and stakeholder responses to the implementation of the ACA that may have affected insurance coverage and related demand for health services. The projections assumed that all states would expand Medicaid under the ACA, that full Medicaid expansion has not occurred, and that these projections also do not account for changes in federal policy related to the private insurance market.