	Introduction

The National Health Service Corps (NHSC) is a clinician recruitment and retention program that aims to reduce health workforce shortages in underserved areas. Under each of these programs, health providers receive either scholarships or loan repayments in exchange for a service commitment at an NHSC-approved facility located in a federally designated health professional shortage area (HPSA, see text box). The three NHSC programs are managed by the Bureau of Health Workforce (BHW) in the Health Resources and Service Administration (HRSA), an agency in the Department of Health and Human Services (HHS). The NHSC was created by the Emergency Health Personnel Act of 1970 to provide an adequate supply of trained health providers in federally designated HPSAs. Since the program's inception, Congress has reauthorized and revised the program several times, with the most recent reauthorization included in the Patient Protection and Affordable Care Act ( P.L. 111-148 , ACA). Historically, the NHSC had been exclusively funded as part of HRSA's discretionary appropriation. The ACA created the CHCF and provided mandatory funding for it over a five-year period (FY2011-FY2015). The fund was intended to supplement the NHSC budget; however, from FY2012 to FY2017, it made up the entirety of the program's funding. The CHCF was initially set to expire at the end of FY2015; however, it was extended for two years (FY2016 and FY2017) as part of the Medicare Access and CHIP Reauthorization Act of 2015 (MACRA, P.L. 115-96 ) ultimately provided mandatory funding for the first two quarters of FY2018, and the Bipartisan Budget Act of 2018 (BBA 2018, P.L. Although the program had not received discretionary appropriations from FY2012 through FY2017, it received $105 million in FY2018 in P.L. 115-141 , with funds directed toward supporting health care providers who provide opioid and other substance use disorder treatment in HPSAs. Recruitment

From FY2011 through FY2017, the most recent year of final data available, the NHSC offered more than 39,000 loan repayment agreements and scholarship awards to individuals who have agreed to serve for a minimum of two years in a HPSA. Field Strength

The number of awards the NHSC makes at any point in time is only one component of program size, as not all awardees are currently serving as NHSC providers. Specifically, NHSC scholars and S2S program participants are still completing their training. As such, the NHSC also measures its field strength, which is the number of NHSC providers who are fulfilling a service obligation in a HPSA in a given year. In FY2017, the most recent year in which data are available, total NHSC field strength was 10,179. Legislative Proposals to Expand NHSC Provider Eligibility

Some individuals and professional groups have advocated for making additional provider types eligible for the NHSC. The Consolidated Appropriations Act, 2018 ( P.L. NHSC providers are located at HPSAs throughout the United States and its territories (see Figure 4 ).
The National Health Service Corps (NHSC) provides scholarships and loan repayments to health care providers in exchange for a period of service in a health professional shortage area (HPSA). The program places clinicians at facilities—generally not-for-profit or government-operated—that might otherwise have difficulties recruiting and retaining providers.
The NHSC is administered by the Health Resources and Services Administration (HRSA), within the Department of Health and Human Services (HHS). Congress created the NHSC in the Emergency Health Personnel Act of 1970 (P.L. 91-623), and its programs have been reauthorized and amended several times since then.
The Patient Protection and Affordable Care Act of 2010 (ACA; P.L. 111-148) permanently reauthorized the NHSC. Prior to the ACA, the NHSC had been funded with discretionary appropriations. The ACA created a new mandatory funding source for the NHSC—the Community Health Center Fund (CHCF), which was intended to supplement the program's annual appropriation. However, between FY2012 and FY2017, the CHCF entirely replaced the NHSC's discretionary appropriation. For FY2018, the NHSC received $105 million from discretionary appropriations in P.L. 115-141 to support awards to expand and improve access to opioid and other substance use disorder treatment providers. The law also reserves $30 million from the $105 million for the new Rural Communities Opioid Response initiative administered by the Federal Office of Rural Health Policy within HRSA. For FY2018, CHCF funding represents 75% of the program's appropriation.
The CHCF is time-limited. Initially an appropriation from FY2011 through FY2015, the CHCF was subsequently extended in the Medicare Access and CHIP Reauthorization Act of 2015 (MACRA, P.L. 114-10) through FY2017 and then extended for an additional two years (i.e., through FY2019) in the Bipartisan Budget Act of 2018 (BBA 2018, P.L. 115-123).
From FY2011 through FY2017, the most recent year of final data available, the NHSC offered more than 39,000 loan repayment agreements and scholarship awards to individuals who have agreed to serve for a minimum of two years in a HPSA. In FY2017, the NHSC made 5,711 awards. The number of awards the NHSC makes is only one component of program size, because not all awardees are currently serving as NHSC providers; some are still completing their training (e.g., scholarship award recipients). As such, the NHSC also measures its field strength: the number of NHSC providers who are fulfilling a service obligation in a HPSA in a given year. In FY2017, total NHSC field strength was 10,179. NHSC providers are currently serving in a variety of settings throughout the entire United States and its territories. The majority of NHSC providers serve in outpatient settings, most commonly at federally qualified health centers.