Why GAO Did This Study From September 2026 through December 2026, GAO is seeking input and feedback on this exposure draft from all interested parties. Please use this link TEGuideComments@gao.gov to provide us with comments on the guide. Federal agencies spend billions of dollars each year buying commercially available off-the-shelf (COTS) products. When agencies want to buy a COTS product, first they need to determine whether a vendor’s product is right for them. One way that agencies assess a product is by conducting testing and evaluation (T&E). Agencies can then use the results of the T&E to inform their purchasing decisions. Prior GAO work has identified problems with how agencies conduct T&E. Also, there is no widely accepted process or organization for sharing best practices for T&E. GAO developed this guide to provide best practices for conducting COTS T&E. GAO has developed this guide to serve multiple audiences: The primary audience for this guide is federal agencies—specifically, T&E practitioners, program managers, and procurement officials. Agency staff can implement the best practices in this guide to improve their T&E, procure effective technologies, and reduce risks of cost and schedule overruns. GAO and other oversight organizations can use this guide to evaluate how effectively federal agencies conduct T&E when buying a COTS product. Vendors can use this guide to evaluate the performance of their products against agency requirements. For more information, contact Karen Howard at HowardK@gao.gov.

What GAO Found Federal buildings often contain special use spaces like meeting rooms and conference centers, some of which may be shared across agencies. Agencies varied in how they shared these spaces in the selected General Services Administration (GSA)-owned and -leased buildings GAO visited. Interviewees, including officials from federal tenant agencies in those selected buildings, said that sharing these spaces can provide benefits, including: access to useful spaces their agency might not otherwise have, reduced costs and more efficient use of space (e.g., agencies do not need to lease or construct individual spaces), and  increased collaboration between agencies. However, interviewees also identified challenges to sharing, such as lack of awareness of what spaces are available or how to reserve them. Illustrative Examples of Special Use Spaces in a Federal Building GSA, which manages federal real property for tenant agencies, publishes an online list of meeting spaces that agencies volunteered to share. The list includes information such as room descriptions and a point of contact to reserve the space. However, the list is not comprehensive—some tenant agencies have not added their space to the list, and some GSA rooms are not on the list. GSA periodically emails agencies to request that they update the list, and it relies on agencies to distribute the list to their staff. However, most agency officials GAO interviewed in selected buildings were not aware of GSA’s list. GSA officials noted that federal turnover in 2025 contributed to reduced awareness of the list. They said that starting in 2025, more of their reminder emails were undelivered. Officials said they worked with agencies to update their contacts, and that they may be able to use other mechanisms to more broadly distribute the list. Improving the comprehensiveness of the list and agency awareness of it could help agencies share special use spaces, which could in turn potentially reduce costs by supporting GSA’s efforts to ensure efficient use of federal space. Why GAO Did This Study In recent years, GSA and others have taken steps to reduce unneeded federal real property, particularly office space, but building utilization across the federal government remains low. The Thomas R. Carper Water Resources Development Act of 2024 includes a provision for GAO to report on the use of special use spaces in federal buildings to determine levels of use and identify opportunities for sharing, collocating, and other efficiencies. This report addresses 1) how agencies share special use spaces in selected GSA-owned and -leased buildings, 2) the reported benefits and challenges related to sharing special use spaces, and 3) GSA’s efforts to promote sharing of special use spaces. GAO conducted in-person site visits at six federal buildings selected for geographic diversity and whether there were multiple tenants, among other criteria. These site visits were composed of 1) a review of data or documentation; 2) observation of special use spaces; 3) interviews with GSA officials; and 4) interviews with officials from federal tenant agencies in those buildings. GAO also reviewed available GSA documentation and assessed GSA efforts against its strategic goals and GAO leading practices for interagency collaboration.

What GAO Found Personal protective equipment (PPE)—such as masks and gloves—helps minimize exposure to hazards, including illnesses. In response to the COVID-19 pandemic (March 2020–May 2023), the Federal Emergency Management Agency (FEMA) and the Department of Transportation (DOT) expedited the transportation of PPE by air and helped mitigate supply chain challenges. FEMA. From March through June 2020, FEMA conducted Project Airbridge, in which FEMA paid for the air transportation of PPE from overseas to the U.S. to reduce shipment times. FEMA funded 437 flights to transport approximately 1.2 billion PPE items, primarily gloves, masks, and gowns. DOT. DOT used selected legal authorities to help expedite the transportation of PPE by air and to provide transportation industry stakeholders with regulatory relief that could have expedited the transportation of PPE. For example, DOT’s Federal Aviation Administration issued exemptions from certain regulations during the COVID-19 pandemic to allow certain passenger air carriers to transport cargo in the passenger cabins of aircraft. DOT and other federal agencies also coordinated with transportation industry stakeholders specifically to mitigate supply chain issues and keep goods moving during the pandemic, which may have expedited the transportation of PPE. Boxes of Personal Protective Equipment Transported in the Passenger Cabin of an Aircraft During the COVID-19 Pandemic Stakeholders GAO interviewed shared perspectives on methods to expedite the transportation of PPE used during the COVID-19 pandemic, and many said that an increased federal role was unnecessary or could have had negative consequences. For example, two stakeholders cited the use of “peel piles” to designate areas at ports for containers from specific shippers as a method used to expedite goods during the pandemic, including PPE. Many stakeholders said they did not think more federal involvement was needed in expediting the transportation of PPE during the pandemic, or that increased federal involvement could have had negative consequences. For example, stakeholders said that federal involvement in prioritizing a container on a ship could have caused delays at ports. Furthermore, several of these stakeholders stated that the private sector and industry partners were better suited to take the lead in expediting the transportation of goods through the supply chain. Why GAO Did This Study During the COVID-19 pandemic, significant challenges, including global demand and supply chain issues, made it difficult to quickly access PPE. Delays in the transportation of PPE may have contributed to the spread of COVID-19, which killed nearly 1.2 million people in the U.S. as of June 1, 2024. Public Law 118-159 includes a provision for GAO to review the expedited transportation of PPE during the COVID-19 pandemic. This report describes, among other things, (1) how DOT and other relevant federal agencies expedited the transportation of PPE during the pandemic, including using selected legal authorities to do so; and (2) selected industry stakeholder perspectives on methods used to expedite the transportation of PPE during the COVID-19 pandemic, including their views on whether an increased federal role was needed. GAO reviewed documentation and interviewed officials from five federal agencies that played a role in expediting the transportation of PPE: DOT, FEMA, Health and Human Services (HHS), the Department of Defense, and the Federal Maritime Commission. GAO also reviewed relevant statutes, regulations, and executive orders and analyzed available data from FEMA and HHS that described the amount and type of PPE that these agencies transported during the COVID-19 pandemic. GAO interviewed a nongeneralizable sample of 21 stakeholders representing three groups relevant to the transportation of PPE: transportation industries, health care distributors, and port authorities. GAO selected these stakeholders based on factors including geographic diversity, involvement in federal efforts to expedite the transportation of PPE, or market share of their respective industry. For more information, contact Elizabeth Repko at RepkoE@gao.gov.

What GAO Found The Federal Aviation Administration’s (FAA) Brand New Air Traffic Control System (BNATCS) has an ambitious goal to significantly accelerate the modernization of outdated air traffic control (ATC) systems. The goal is to be achieved at an unprecedented speed. The first of two phases aims to modernize communication, surveillance, weather, and training systems, among other things. For example, FAA plans to modernize voice radio systems 9 years earlier than initially planned. Phase 1 is to be fully completed by December 2028. In July 2025, Congress appropriated $12.5 billion to support BNATCS and FAA is using most of the funds for phase 1. For phase 2, FAA plans to develop new automation systems to track aircraft and optimize traffic. FAA stated that they will need approximately $10.2 billion for this phase (not including facilities). FAA does not yet have an estimated date for when phase 2 will be started or completed. FAA has made progress in implementing portions of phase 1. For example, as of May 2026, FAA reported replacing 2,560 of 5,170 old and frail copper wires with high-speed fiber optic communications cables. Copper Wires from the 1960s Are Being Replaced with Fiber Optic Cables FAA has not developed a comprehensive and well-documented lifecycle cost estimate for BNATCS. In June 2026, FAA officials provided high-level estimates per program for phase 1. However, officials were unable to provide the analysis that supported these figures. In addition, officials acknowledged that the estimate does not include government costs, most of the operations costs for phase 1, or any of the costs for phase 2. In addition, FAA has not developed an integrated master schedule for phase 1. Instead, FAA has 11,389 individual project schedules that are not integrated. As a result, individual projects are scheduled for installations at the same sites, generally without optimizing the schedules to reduce impacts to controller operations. Officials stated they have plans to address this issue, however; they did not have a time frame for when the issue would be resolved. While accelerating this modernization is critical, FAA’s lack of a reliable lifecycle cost estimate and an integrated master schedule introduce heightened risk to BNATCS. GAO’s decades-long bodies of work on acquisitions and FAA modernizations indicate that these risks increase the likelihood of FAA repeating its history of cost overruns, delays, and unmet performance targets. If these risks are realized, FAA would need to continue to rely on severely outdated systems that are prone to failure leading to more flight delays and safety incidents. Why GAO Did This Study FAA air traffic controllers rely on a myriad of legacy systems to monitor weather, conduct surveillance, and manage communications for up to 45,000 flights per day. This aging and unreliable technology has contributed to an increase in flight delays and aviation incidents. FAA has attempted to modernize ATC systems since the 1980s, but has experienced challenges and delivered limited results. In September 2024, GAO reported that over 75 percent of FAA’s 138 ATC systems were unsustainable or potentially unsustainable. GAO also reported that FAA was not moving fast enough to modernize its systems. In May 2025, the Secretary of Transportation announced the latest FAA modernization effort, BNATCS. Due to the importance of successfully implementing this latest modernization effort, GAO was asked to examine FAA’s progress. GAO’s objectives were to (1) identify the initial plans and status of BNATCS and (2) assess the extent to which FAA has established a cost estimate and schedule to support BNATCS. GAO analyzed FAA’s planning and implementation materials. GAO also assessed available schedule and cost estimation documentation and compared them to best practices. Further, GAO interviewed FAA officials regarding BNATCS status, cost, and schedule.