An adequate supply of health care professionals is necessary to ensure access to needed health care services. HRSA estimated that there were approximately 780,000 physicians and 261,000 physician assistants and advanced practice registered nurses engaged in patient care in 2010. Part of maintaining an adequate health care workforce involves projecting the future supply of health care professionals and comparing that supply to the expected demand for health care services to determine whether there will be enough providers to meet the demand. Such projections can provide advance warning of shortages or surpluses so that health care workforce policies, such as funding for health care training programs, can be adjusted accordingly. In its 2008 physician workforce report, HRSA noted that due to the long time needed to train physicians and to make changes to the medical education infrastructure, policymakers and others need to have information on the adequacy of the physician workforce at least 10 years in advance. We have also previously reported that producing supply and demand projections on a regular basis is important so that estimates can be updated as circumstances change. Health care workforce projections typically measure the supply of health care professionals and the demand for services in a base year and predict how each will change in the future given expected changes in the factors that affect supply and demand. On the supply side, “stock and flow” models are commonly used; these models start with the current number of health care professionals, add new entrants to the workforce, such as students who complete their medical training, and subtract providers who are expected to leave the workforce, such as those who retire. Factors influencing supply include the capacity of educational programs to train new health care professionals, the number of patients that health care professionals are able to care for, and attrition rates. On the demand side, a utilization-based approach is often used, which measures the current utilization of health care services and projects that pattern of utilization forward, making adjustments as the population receiving services changes over time. Factors affecting demand include economic conditions, population growth, and changing population demographics such as aging or an increase in insurance coverage. At the federal level, HRSA is responsible for monitoring the supply of and demand for health care professionals and disseminating workforce data and analysis to inform policymakers and the public about workforce needs and priorities. To meet this responsibility, HRSA conducts and contracts for health care workforce research to document and project shortages and to examine trends that influence the supply and distribution of health care professionals, as well as the demand for their services. In 2008, HRSA issued a physician workforce report containing national supply and demand projections for physicians through 2020, which was based on the agency’s physician workforce models: the Physician Supply Model (PSM) and Physician Requirements Model (PRM). Using these models, HRSA projected a shortfall of approximately 49,000 FTE physicians by 2020. The PSM is a “stock and flow” model, which projected the future supply of physicians by taking the number of physicians from a base year (2000), adding new entrants, and subtracting physicians lost through retirement, disability, or death. The PSM projected both active supply (the number of individual physicians) and the effective supply (the number of FTE physicians accounting for the number of hours worked). The number of FTEs was determined by the average number of hours worked for physicians in each specialty by gender and age group. The PRM is a utilization-based model, which projected the demand for physicians starting with the utilization of health care services in 2000 by age, sex, geographic location, and insurance coverage type (see fig.1). The PRM assumed that supply and demand were in equilibrium in 2000, that is, that there were enough physicians to meet the demand for health care services. The PRM’s baseline projection also assumed that patterns of utilization would not change, although HRSA created some alternative scenarios showing how utilization might change (and therefore affect demand) because of factors such as economic growth. HRSA also included a scenario that accounted for the effect of nonphysician providers, such as nurse practitioners and physician assistants, who may offset the demand for physicians by providing services that otherwise would have been provided by physicians. HRSA and others have noted that a drawback of the utilization-based approach, which carries forward current utilization patterns, is that when calculating the number of physicians needed, any current imbalances in the system, such as populations that may be underserved, or any overutilization of health care services are also carried forward. HRSA’s 2008 physician workforce report predates PPACA, which was enacted in 2010. PPACA contains provisions that have the potential to affect both health care workforce supply and demand, which increases the uncertainty of health care workforce projections (see table 1). Several health care workforce researchers have published estimates of the effects of PPACA insurance coverage expansions on workforce supply and demand. These studies found varying estimates for the number of additional primary care providers required to meet the needs of the newly insured population, ranging from 4,300 to 8,000 providers. The variations in these projections are the result of differences in methodologies and assumptions used in modeling. AAMC also increased its overall projection of physician shortages for 2025 by 6,200 FTE physicians, on the basis of expected increases in health care demand as a result of greater rates of insurance coverage under PPACA, among other factors. PPACA provides for the establishment of new delivery models such as accountable care organizations (ACO) and patient- centered medical homes (PCMH). ACO models consist of integrated groups of providers who coordinate care for a defined patient population in an effort to improve quality, reduce costs, and share in any savings. The PCMH model is a way of organizing and delivering primary care that emphasizes comprehensive, coordinated, accessible, and quality care built on strong patient-provider relationships. Such models also encourage shifting care provision to nonphysician providers, potentially decreasing the need for additional physicians. Some researchers have stated that they expect new delivery models, such as ACOs, will have a significant and lasting effect on the broader health care marketplace, though research shows conflicting results as to how these new delivery models will affect the supply of and demand for health care professionals. PPACA also mandated the establishment of the National Health Care Workforce Commission and required HHS to establish the National Center for Health Workforce Analysis (NCHWA) to collect and analyze data on the health care workforce and evaluate workforce adequacy. The National Health Care Workforce Commission was charged with conducting analyses of health care supply and demand and submitting annual reports to Congress that included recommendations. However, this commission has not received appropriations and therefore has not met since it was appointed. In 2010, HRSA established NCHWA within its Bureau of Health Professions. NCHWA is responsible for developing and disseminating accurate and timely data and research on the health care workforce, among other things. In 2012, NCHWA produced a timeline for updating HRSA’s workforce projections, as we recommended. Since its last published report on physician supply and demand in 2008, HRSA has initiated work to produce new workforce models and reports, but has not published any new reports containing national workforce projections. Specifically, HRSA has missed one of its publication goals for new workforce projections and has created a revised timeline that postpones future publications. Given that HRSA’s 2008 report was based on 2000 data, the most recent projections available from HRSA to Congress, researchers, and the general public to inform health care workforce policy decisions are based on data that are more than a decade old. From 2008 to 2012, HRSA awarded five contracts to three research organizations to update or create new workforce projection models, generate new national workforce projections, and produce reports. (See table 2 for a summary of the contracts and their status.) As of July 2013, HRSA had received three reports resulting from these contracts, and two more reports were under development. Contractor A delivered the first report, which includes projections for the primary care workforce to 2020, in July 2010, but HRSA was still reviewing and revising the draft as of July 2013. HRSA officials said that this primary care report has required extensive consultation with other HHS components to ensure that the methods used were consistent with other ongoing workforce-related work within the department. In addition, officials said that significant revisions were required to incorporate the effects of PPACA. Contractor B delivered the second report, which updated HRSA’s 2008 physician workforce projections using more recent data, in February 2011. However, according to HRSA officials, the agency decided not to publish this report because it did not incorporate nonphysician providers, which they have since determined should be accounted for when assessing the adequacy of the health care However, officials also said that research conducted under workforce.this contract regarding the health care workforce effects of PPACA was incorporated into HRSA’s later projection models. The third report, the clinician specialty report, which projects the supply of and demand for health care professionals by specialty through 2025, was delivered in November 2012 and is still under HRSA’s review. HRSA has missed one of its timeline goals for finalizing its review and publishing new reports containing national projections and has created a new timeline that postpones publication dates for this and two other health care workforce reports. Although HRSA’s original timeline stated that the clinician specialty report would be published in December 2012, HRSA’s revised timeline states that this report is expected to be published in the summer of 2014. The revised timeline also included new publication dates for HRSA’s report on the primary care workforce and for reports based on its new microsimulation models. (Table 3 shows HRSA’s original and revised timelines for publication.) HRSA attributed the delay in publishing the clinician specialty report to data challenges and modeling limitations. For example, HRSA officials cited limited research and data on the effects of new health care delivery models being funded and tested in response to PPACA.