Federal policy makers have a long-standing interest in science, technology, engineering, and mathematics (STEM) education. This interest is largely driven by concerns about the national science and engineering workforce, which is widely believed to play a central role in U.S. global economic competitiveness and national security. The U.S. STEM education system is a primary source of scientists and engineers in the United States. Approximately 6% of the U.S. workforce was employed in a STEM field in 2011. About 70% of those workers had at least a bachelor's degree. Further, of college graduates who were employed in a STEM field, 73% had a science or engineering major. Given the oft-cited connection between STEM education and key national priorities, federal policy makers have historically paid close attention to the U.S. STEM education system. The federal STEM education effort is wide-ranging. Analysts have identified between 105 and 252 STEM education programs and activities at 13 to 15 federal agencies. Annual federal appropriations for STEM education are typically in the range of $2.8 billion to $3.4 billion. Published inventories of the federal STEM education effort identify the Department of Education (ED), National Science Foundation (NSF), and Department of Health and Human Services (HHS) as key agencies in the federal effort. Of these, the NSF has the most STEM education funding and largest number of programs (typically). The foundation is also the only federal agency whose primary mission includes supporting education across all fields of science and engineering. As such, the NSF is a key component of the federal STEM education portfolio. Funding for STEM education decreased as a percentage of the total NSF budget between FY2003 and FY2012. Further, funding levels for the foundation's main education account were lower than the previous year in both FY2011 and FY2012. FY2013 current plan funding for the main education account appears to be close to FY2012 levels. The significance of these funding trends for NSF's education and research missions, as well as for the federal STEM education effort overall, depends in part on how these changes fit within historical funding trends at the NSF. This report analyzes those trends—and addresses selected STEM education policy issues—in order to place the conversation about federal funding for STEM education at NSF in broader fiscal and policy context. This report examines actual funding for the NSF from FY2003 to FY2012 in current and constant (2005) dollars. Congress provides appropriations in current dollars, so current dollar funding data align with annual appropriations measures and congressional actions, while constant dollar data adjust for the effects of inflation and provide insight into purchasing power. This report also analyzes the distribution of total NSF funding by appropriations account and by character class. The character class analysis adjusts for programs that draw from more than one appropriations account but serve the same program or activity. Over time, changes in the distribution of funding may reflect changing policy priorities. Several other introductory points should be noted. This report uses the following terms for the major appropriations accounts at NSF: "R&RA" or "main research account" for Research and Related Activities, "E&HR" or "main education account" for Education and Human Resources, "MREFC" or "main construction account" for Major Research Equipment and Facilities Construction, "AOAM" for Agency Operations and Awards Management, "NSB" for National Science Board, and "OIG" for Office of the Inspector General. This report uses the following terms for major activities: "R&D" or "research activities" for research and development-related activities, "E&T" or "education activities" for education and training-related activities, and "NIA" for non-investment activities. Non-investment activities are primarily administrative activities (e.g., travel and compensation costs for proposal review panelists). The analysis in this report is based on budgetary data from the NSF's annual budget requests to Congress from FY2005 to FY2014 and from information provided to CRS by NSF. Appropriations account data come from the "Overview" sections of the NSF budget requests; funding data by character class come from the "Quantitative Data Table" sections. CRS adjusted the appropriations account data for FY2003 to FY2005 to reflect the transfer of the Experimental Program to Stimulate Competitive Research (EPSCoR) between major accounts. This analysis treats EPSCoR as a research account program for all years in the data set. NSF adopted its current appropriations account structure in 2003. FY2003-FY2012 are the most recent years for which actual funding data are available and comparable. NSF programs are often co-funded (e.g., funded by two or more appropriations accounts). Budgetary data that are broken down by character class adjust for co-funding and provide insight into what NSF actually spends on a given activity. Funding levels for FY2009 and FY2010 do not include funding from the American Recovery and Reinvestment Act (AR&RA, P.L. 111-5 ) because NSF treated these funds as supplemental in its budget calculations. To generate constant dollar (e.g., inflation-adjusted) data in FY2005 dollars CRS used the Office of Management and Budget (OMB) deflator published in Table 10.1 of the OMB's Historical Tables and accessed on December 23, 2013. Data used in this report may be found in Appendix A and Appendix B . The NSF's budget can be broken down by character class. According to the NSF, its two primary activities are research and development (R&D) and education and training (E&T). The NSF also has a category for what it calls "non-investment activities," or NIA, which pays for items such as proposal review panel travel and compensation costs, invitational travel, and other administrative activities. Unlike appropriations accounts, which show how Congress provides funding to the foundation, the character class perspective adjusts for co-funding (i.e., when programs are supported by more than one appropriations account) and provides insight into total funding for the foundation's two primary missions (e.g., research and STEM education). Figure 1 shows how NSF current dollar funding for E&T and R&D activities changed between FY2003 and FY2012. (See Appendix A for data.) The total current dollar increase in NSF funding between FY2003 and FY2012 was $1.735 billion, or 32% more than the FY2003 baseline of $5.369 billion. During this period, current dollar funding for R&D increased by $1.762 billion while current dollar funding for E&T decreased by $95 million. Funding for R&D increased more or less steadily, while funding for E&T fluctuated. E&T funding levels ranged from a high of $941 million in FY2004 to a low of $783 million in FY2006. The median funding level for E&T during the observed period was $840 million. FY2012 funding for E&T was below the FY2003 level. When expressed in constant (2005) dollars, funding for R&D experienced a relatively flat period from FY2005 through FY2008. (See Figure 2 .) The sharp increase in constant dollar R&D funding between FY2009 and FY2010 coincides with the second year of funding under the America COMPETES Act ( P.L. 110-69 ). R&D funding levels have stayed about the same since then. Constant dollar funding for E&T generally trended downward between FY2003 and FY2012—ranging from a high of $972 million in FY2004 to a low of $696 million in FY2012. Median constant dollar funding for E&T activities during the observed period was $797 million. In constant (2005) dollars, total NSF funding increased by $447 million—from $5.684 billion to $6.131 billion—between FY2003 and FY2012. Funding for R&D increased by $748 million while funding for E&T decreased by $258 million during this same period. (See Figure 3 .) Given that funding for R&D grew in excess of the total NSF increase, and that funding for E&T experienced negative growth, at least some of the growth in funding for R&D between FY2003 and FY2012 appears to have come from E&T. The distribution of NSF funding by character class also changed between FY2003 and FY2012. As Table 1 shows, the percentage of the NSF budget dedicated to E&T activities generally decreased while the percentage dedicated to R&D activities generally increased. This is consistent with the previous finding that most of the total increase in NSF funding during the observed period went to R&D. Some of the increase in the percentage of the NSF budget dedicated to R&D may have come from NIA. (See "Note," Table 1 .) Congress provides funding to the NSF via appropriations accounts, not by character class. Analysis of appropriations account trends, therefore, aligns more closely with congressional action than analysis by character class. This section focuses on changes in congressional appropriations for the R&RA and E&HR accounts because these accounts are the primary sources of support for NSF mission activities. As with the previous analysis of character class trends, this section examines both current and constant (2005) trends in funding for these accounts. Total current dollar appropriations to NSF increased from $5.369 billion to $7.105 billion between FY2003 and FY2012. Of this $1.735 billion increase, 93.0% or $1.615 billion went to R&RA. Current dollar appropriations for E&HR decreased by $15.2 million (-1.8%) during the same period. Figure 4 shows the current dollar trends in R&RA and E&HR from FY2003 to FY2012. (See Appendix B for data.) Both R&RA and E&HR experienced current dollar reductions from the prior year in FY2005 and FY2011.