The federal executive branch controls an extensive real property portfolio that includes more than a quarter of a million owned and leased buildings. These buildings have been acquired over a period of decades to help federal agencies fulfill their unique missions. Agencies hold buildings with a range of uses, including offices, warehouses, barracks, laboratories, and hospitals. The cost of operating and maintaining these diverse properties, which total more than 2.8 billion square feet, exceeded $21 billion in FY2014. Oversight of the federal real property portfolio has been a priority for oversight committees in recent congresses, with committees in both the House and the Senate holding hearings and introducing legislation to improve, in particular, the management of federal buildings. Congressional oversight has focused in large part on four building management issues identified by the Government Accountability Office (GAO), which has put real property on its annual "high-risk list" since 2003. In recent testimony before the Senate Committee on Homeland Security and Governmental Affairs, David Wise, the Director of Physical Infrastructure Issues for GAO, identified three key challenges that agencies face when managing their real property portfolios: Maintaining more real property than it needs (including unutilized and underutilized buildings); Relying on leasing when ownership of new space would be more cost efficient; and Making real property management decisions using unreliable data. This report focuses on the challenges to effective oversight posed by the lack of accurate and reliable real property data, particularly as it relates to the disposal of unneeded buildings and the government's overreliance on costly leases. The balance of this report consists of three sections. The first section analyzes potential weaknesses in the data available to Congress on unutilized and underutilized buildings. The second section examines the nature of the government's reliance on costly leases and discusses which data elements might enhance oversight of leased building space. The final section of the report discusses options for policymakers to consider should they seek to address these data issues. As noted, the federal executive branch agencies hold more than 250,000 buildings with a range of purposes, suited to the unique mission of each agency. As agencies' missions change over time, so do their real property needs, thereby rendering some assets less useful or unneeded altogether. Healthcare provided by the Department of Veterans Affairs (VA), for example, has shifted in recent decades from predominately hospital-based inpatient care to a greater reliance on clinics and outpatient care, with a resulting change in space needs. Similarly, the Department of Defense (DOD) decreased its force by 36% after the Cold War ended, and has engaged in several rounds of base realignments and installation closures. In response to these changes, agencies have housed fewer employees in certain facilities, and have shifted other personnel into new space, leaving behind thousands of buildings that are vacant (unutilized) or only partially occupied (underutilized). To reduce the amount of unneeded space in the government's portfolio—and its associated costs—agencies are required to continuously survey their real property assets and identify buildings they can dispose of in their entirety (transfer, donate, or sell), and unoccupied space within buildings that could be filled by new tenants. Agencies are then required to report those properties as excess to the General Services Administration (GSA), which is responsible for the disposition of unneeded space for all executive branch agencies, except those with their own independent statutory disposal authority. To that end, GSA seeks out both federal and nonfederal tenants to fill empty space in underutilized federal buildings, and follows a statutorily -prescribed process for disposing of unutilized buildings, which is described briefly below. Agencies must first offer to transfer excess properties to other federal agencies, which generally pay market value for excess properties they wish to acquire. If no federal agency wants an unneeded property, then it is declared "surplus" and made available to state and local governments, and nonprofits. These entities may have surplus property transferred to them for a discount of up to 100% of fair market value, provided they use the property for a public benefit. This type of transfer is called a public benefit conveyance, and to qualify, the property must be used for one of the following purposes: Homeless services Corrections Law enforcement Public health Drug rehabilitation Education Parks and recreation Seaport facilities Wildlife conservation Highways Emergency management response Historic monuments Public airports Housing Pursuant to Title V of the McKinney-Vento Homeless Assistance Act, surplus properties must be made available for serving the homeless before being made available for other public benefit uses. The Department of Housing and Urban Development (HUD) is responsible for reviewing surplus property to determine if it is suitable for homeless use. If a property is determined to be unsuitable for homeless use, then it becomes available for other public uses at that time. Surplus properties not conveyed for public benefit are then available for sale at fair market value or are demolished if the property could not be sold due to the condition or location of the property. Given that, by one estimate, the government spends more than $1.6 billion dollars operating and maintaining unutilized and underutilized buildings each year, oversight of the disposal process has been of ongoing interest to Congress. Access to comprehensive, reliable data on federal buildings is crucial to congressional oversight, because that information may be used to determine if the disposal process is operating efficiently and effectively, identify obstacles to timely disposition, and accurately assess the costs and benefits of different real property policies, among other things. The primary source of real property data available to Congress is the Federal Real Property Report (FRPR), an annual report that provides aggregate data on agency real property portfolios. The report, which is published by an interagency group of real property officials known as the Federal Real Property Council (FRPC), draws on information stored in a database maintained by the General Services Administration (GSA), the Federal Real Property Profile (FRPP). The Council establishes data definitions and determines what data to collect and report, while GSA actually collects and maintains the data. GSA's database, which is populated with detailed information about executive branch agency properties, holds a wide range of data that could be useful to congressional oversight—but its usefulness is limited by two factors. First, the data are unreliable. Poor quality data is one of the primary reasons GAO has put real property management on its high-risk list for the past 12 years. Moreover, the annual real property report does not include some data that GSA has collected which might be considered important to oversight committees, particularly data related to unutilized and underutilized buildings. Second, without direct access to GSA's database—which Congress currently lacks—policymakers only see the data that GSA and the real property council choose to publish. The balance of this section is a discussion of these issues as they pertain to specific data elements that many argue are necessary for effective congressional oversight. Aggregate data on the number of unutilized and underutilized buildings is often seen as key to effective oversight because it can enable policymakers to understand the scale of the problem and its costs. The larger the problem, the higher the costs and the more time policymakers may choose to devote to the issue. The reliability of the data available to Congress, however, has been characterized as poor on several counts. The FRPR, the only comprehensive source of information about unutilized and underutilized buildings, has numerous limitations. First, the source of the report's data, GSA's FRPP database, has been criticized repeatedly by GAO for its inability to provide accurate, consistent information on unneeded property. GAO found, for example, that some buildings reported to the FRPP as underutilized were fully occupied, while others reported as occupied were, in fact, vacant. GAO asserted that because these data are not reported uniformly, they "can have no collective meaning when amassed in a single database." The inconsistent quality of utilization data contributed to GAO's opinion that the FRPP data—which come to policymakers through the annual real property report—may not "provide an adequate tool for decision making or measuring performance." Changes to building utilization definitions have also limited the usefulness of reported real property data. In FY2011, and again in FY2013, the FRPR used different definitions of unutilized and underutilized space, resulting in very different totals for each category. The FY2010 FRPR identified 6,700 buildings as unutilized buildings and 71,000 as underutilized. The definitions used in the FY2011 and FY2012 FRPRs did not categorize properties as unutilized or underutilized, and so cannot be compared to prior or subsequent years. In FY2013, after the definitions changed again, agencies reported 3,100 buildings as unutilized and 2,400 as underutilized. Under the latest space utilization definitions, the number of buildings categorized as unutilized decreased by 54%, and the number categorized as underutilized decreased by 97%. With such significant changes in the numbers of buildings in each category, it is unclear which definition gives the more accurate picture of the scale of the problem, and therefore how policymakers can best address it. The scale of the problem of unutilized and underutilized building space may be described in terms of cost. The amount of funding spent operating and maintaining buildings that are empty or only partially occupied may help policymakers determine whether addressing the problem should be a priority. Cost data may also help policymakers evaluate the cost-effectiveness of various policy alternatives—the greater the potential for savings, the wider the range of policy options that could provide net fiscal benefits to the government. The FRPR does not include the cost of operating unneeded building space. The data are collected, and, in fact, were included in the FRPR as recently as FY2010, when the government spent $112 million operating unutilized buildings and another $1.6 billion operating underutilized buildings.