DOD’s MILCON appropriations are used to fund the acquisition, construction, installation, and equipping of temporary or permanent public works, military installations, facilities, and real property needed to support U.S. military forces in the United States and overseas. As with other DOD activities, no funds may be appropriated in any fiscal year or obligated or expended for MILCON activities unless such funds have been specifically authorized by law. Each year, the National Defense Authorization Act authorizes amounts to be appropriated in each of the 18 programmatic MILCON appropriations accounts. Individual or conference committee reports accompanying each fiscal year’s National Defense Authorization Act provide specific congressional direction on authorized funding levels designated for specific construction projects supported by the various MILCON accounts. Similarly, conference committee reports or explanatory statements accompanying each fiscal year’s appropriations acts establish appropriated funding levels for MILCON projects. The process through which the active component requests funding for construction projects is supported by DOD’s Form 1391 Military Construction Project Data (Form 1391). The Form 1391 is to be used to support each project proposed for inclusion in the MILCON appropriations request submitted concurrently with all other DOD appropriations requests annually. The forms are to be used for both new projects as well as urgent unforeseen projects. The Form 1391 describes the scope, total project costs, and estimates of specific project elements. Costs associated with other project elements such as contingency and supervision, inspection, and design are also to be captured and included in the total requested amount. Finally, the Form 1391 is to include a description of the proposed construction and a requirements statement indicating what requirement the project provides. Project budget estimates are initially developed at the installation level and are provided to the next responsible level for review, validation, refinement, prioritization, and approval. Administrative support is to be provided when requested across the departments, but ultimately the installation is the originator and the primary responsible entity in developing the completed Form 1391. MILCON appropriations are generally available for obligation for 5 fiscal years, at which time the appropriation expires. For 5 years after they expire, appropriations are available for limited purposes, such as liquidating obligations made during the period of availability or adjusting contract costs. After these 5 years, any remaining unexpended amounts, whether obligated or unobligated, are canceled and returned to the U.S. Treasury. Once funds are returned to the U.S. Treasury, they are no longer available for any purposes. DOD obligates its appropriations throughout the period in which the appropriation is available. An “unobligated balance” is the difference between the total appropriation amount and total obligations made against the appropriated amounts. An “unexpended balance” is the total of obligated but unliquidated and unobligated amounts. According to DOD officials, available but unobligated amounts no longer needed may be either rescinded by Congress or reprogrammed to other MILCON projects that the active component identifies as needing additional funding. Reprogrammed amounts may be used to fund other projects where there are shortfalls; for projects authorized by Congress but not specifically funded through the appropriations process; for emergency projects, such as for facilities destroyed by fires. DOD’s flexibility to reprogram without congressional approval is limited by the amount to be reprogrammed to a particular project. DOD’s Financial Management Regulation requires prior congressional approval for a reprogramming that would result in an increase exceeding 25 percent of a project’s authorized base amount or $2 million, whichever is less. Prior approval is not required when established costs or project-related thresholds are not reached. According to DOD officials, reprogrammings requiring congressional approval are called “above-threshold reprogrammings” and those that do not are called “below-threshold reprogrammings.” DOD designates construction agents for the military departments and defense agencies with primary responsibility for developing and refining MILCON proposals and cost estimates, and to manage the design and construction of projects. Typically, the Army Corps of Engineers is the construction agent for Army MILCON-funded projects and the Naval Facilities Engineering Command is the construction agent for Navy and Marine Corps MILCON-funded projects. Either of those DOD entities can be the construction agent for the defense agencies and activities, such as for the Missile Defense Agency or Defense Education Activity, with the approval of the military department having jurisdiction of the real property facility. However, both the Army and the Navy may use each other’s construction agent if it is in the interest of efficiency and cost- effectiveness or when otherwise considered appropriate. The Air Force may use either the Army Corps of Engineers or Naval Facilities Engineering Command for its projects. Additionally, the Air Force Civil Engineer Center, although not a designated construction agent, reviews and approves requirements for Air Force MILCON cost estimates, and in some cases may design and construct Air Force projects where both the Air Force and the commander of the assigned construction agent agree that it is the most efficient, expeditious, and cost-effective means to complete the project. Within DOD there are two levels of military construction guidance: the Unified Facilities Criteria and component-level guidance. The Unified Facilities Criteria are overarching, DOD-wide technical manuals and standards used for planning, design, construction, restoration, and maintenance of DOD facility projects. The Unified Facilities Criteria was designed to standardize and streamline the process for developing, maintaining, and disseminating criteria in support of MILCON. The Unified Facilities Criteria contains guidance describing methods, procedures, and formats for the preparation of construction cost estimates and construction contract modification estimates, among other types of guidance. The Unified Facilities Criteria is to be used to the greatest extent possible by all the DOD regardless of funding source. In addition to the Unified Facilities Criteria, the military departments and agencies have also developed their own internal guidance on MILCON, providing further direction on conducting activities such as cost analysis and determining facility requirements. We developed the GAO Cost Estimating and Assessment Guide: Best Practices for Developing and Managing Capital Program Costs (Cost Guide) to assist federal agencies in developing reliable cost estimates and also as a tool for evaluating existing cost estimating procedures. To develop the Cost Guide, our cost experts assessed measures applied by cost estimating organizations throughout the federal government and industry and considered best practices for the development of reliable cost estimates. While the Cost Guide has a focus on developing cost estimates in the context of government acquisition programs, it outlines best practices that are generally applicable to cost estimation in a variety of circumstances. These best practices can be used to assess (1) the specific project cost estimates an agency develops to determine whether they meet the four characteristics—comprehensive, well-documented, accurate, and credible—for being reliable and (2) an agency’s cost estimating guidance and procedures to see how well they incorporate all the steps needed for producing a high-quality cost estimate. Figure 1 shows the four characteristics and associated best practices for each that define a reliable cost estimate and table 1 shows the 12 steps identified in the Cost Guide that, if followed correctly, should result in high-quality cost estimates that management can use for making informed decisions. During fiscal years 2005 through 2016, Congress appropriated about $66 billion in MILCON funds to the active component and, as of September 30, 2016, the active component had obligated all but about $5.1 billion and expended all but about $11 billion of those funds. Of the $5.1 billion that remains unobligated, about $4.6 billion was unexpired and available for new obligations (i.e., from fiscal year 2013 through 2016 appropriations). Table 2 shows the active component’s combined MILCON appropriations, obligations, and unexpended funds from fiscal year 2005 through fiscal year 2016. In general, during the early first few years of a MILCON appropriation available for 5 years, it is often likely that most of the funds will remain unobligated. For example, as shown in table 2 above, of the nearly $3.9 billion appropriated for military construction for the active component from the fiscal year 2016-2020 appropriation, only about $1.1 billion had been obligated as of September 30, 2016. This is not surprising given the time that it takes to award, obligate and disburse funds for projects. Ultimately, though, as an appropriation nears its expiration date, all or nearly all of the amounts have generally been obligated. In fact, as shown in table 2, for each MILCON appropriation received by the active component prior to fiscal year 2013 (fiscal years 2005 through 2012), less than 2 percent of each year’s appropriation was unexpended as of September 30, 2016. In appendix II, we provide additional analysis of the active component’s unexpended and unobligated balances, by appropriation year and by military department. Although ultimately, the active component obligates and expends most of its MILCON appropriations, the active component can experience a wide range of differences between initial cost estimates and final costs during the execution of individual MILCON projects, resulting in savings or shortfalls depending on the project. For example, we found that from fiscal year 2010 through fiscal year 2016, the active component achieved about $4.2 billion in MILCON project savings as a result, for example, of canceled projects, projects with lower than expected contractor bids, or the use of less expensive building materials. In appendix III, we provide additional analysis of the active component’s estimated initial costs and the contract award amounts that were funded by MILCON appropriations for fiscal year 2010 through fiscal year 2016. The active component reprogrammed about $1.6 billion in MILCON appropriations to fund shortfalls caused by emergency projects, projects that were authorized but did not receive specific appropriations, and projects needing additional funding in fiscal years 2010 through 2016. Of this amount, the Army reprogrammed about $789 million of about $14 billion in appropriated MILCON funds; the Navy, about $535 million of about $14 billion in appropriated MILCON funds; and the Air Force, about $295 million of about $7 billion in appropriated MILCON funds. Table 3 shows the number and amounts of above-threshold reprogrammings by the active component for fiscal years 2010 through 2016. As seen in table 3, for any given year there are typically hundreds of millions of dollars reprogrammed. There are generally multiple active or canceled projects that result in cost savings, which may be used to fund authorized but not specifically funded projects. Below are three examples where the active component funded MILCON projects with amounts reprogrammed from other projects: Repair Shop at Andersen Air Force Base, Guam: This is an Air Force project to construct a pacific air resiliency low observable/corrosion control/composite repair shop in Guam. It is an authorized project that did not receive specific funding during the appropriation process but was fully funded by reprogrammed cost savings from active construction projects. Congress authorized $34.4 million for the repair shop in fiscal year 2015; however, no funds were specifically appropriated for the project. According to Air Force officials, since this was their top unfunded military construction priority, they used $34.4 million in savings achieved from other projects to construct the repair shop. Table 4 lists the three projects whose MILCON funds were reprogrammed for the repair shop at Andersen Air Force Base in Guam. Training Facility at the Naval Air Station at Mayport, Florida: This is a Navy project to construct a littoral combat ship training facility in Florida. It is a specifically funded project requiring additional funds that received reprogrammed amounts from a canceled project. In fiscal year 2014, the initial cost as listed on the Form 1391 was estimated to be $20.5 million, but project costs increased by 41 percent to an estimated $28.9 million, according to a fiscal year 2016 reprogramming request to Congress. As detailed in the reprogramming request, the Navy attributed the increased cost to underestimated mission simulator and communication line requirements. To fund the increased costs, the Navy used $8.3 million in savings from a canceled project to complete the facility. Table 5 lists the canceled project that resulted in funds being reprogrammed for the training facility at Mayport. Barracks at Presidio of Monterey, California: This is an Army project to construct a trainee barracks in California. It is a specifically funded project in need of additional funds that received reprogrammed amounts from active and canceled construction projects. In fiscal year 2011, the initial cost for the project as listed on the Form 1391 was estimated to be $63 million, but project costs increased by 51 percent to $95 million, according to a fiscal year 2015 reprogramming request to Congress. As detailed in the reprogramming request, the Army attributed the increased costs to a 3-year delay in construction and the need to move the project to a small, steep-terrain site. The reprogramming request further noted that the delay in construction was due to the discovery at the proposed construction site of a seismic fault and a plant that is an endangered species. To fund the increased costs, the Army sought to reprogram funds from the savings achieved from the active and canceled projects. Table 6 lists the projects that generated the reprogrammed funds used for the barracks at Presidio. Our analyses of the cost estimates for three selected projects shows that the cost estimates were not reliable, and DOD’s cost estimating guidance does not fully incorporate all the steps needed for producing reliable estimates. We examined the cost estimates of three high-value military construction projects and noted that the initial cost estimates increased for all three projects, with cost estimates for two of the projects increasing by over 30 percent and the other, by about 7 percent. Specifically: Strategic Command Operations Building, Offutt Air Force Base, Nebraska. The project to construct a nuclear, space, and network command and control operations building for the command at Offutt Air Force Base, Nebraska, increased from an initial cost estimate in fiscal year 2012 of $564 million to $601 million in fiscal year 2014 (or a 7-percent increase). According to a fiscal year 2014 reprogramming request to Congress, the Air Force attributed the increased cost to the fact that the project team did not appreciate the full scope, complexity, and risk of such an information technology- intensive project. These cost issues are similar to challenges we have reported on for other information technology-intensive MILCON projects. The Air Force is the project owner and the Army Corps of Engineers is the construction agent for this project. Command Headquarters and Cyberspace Operations Building, Fort Meade, Maryland. The project to construct a command headquarters and cyberspace operations building with sensitive compartmented information facility in Fort Meade, Maryland, increased from an initial cost estimate in fiscal year 2013 of $84 million to $110 million in fiscal year 2015 (or a 31-percent increase). As detailed in the fiscal year 2015 reprogramming request, the Navy attributed the increased cost to higher than expected construction costs due to increased demand on the labor workforce in the Washington, D.C./Baltimore area and underestimated electrical power requirements. The Navy is the project owner and the Army Corps of Engineers is the construction agent for this project. Elementary School Camp Foster, Japan. The project to replace an elementary school at Camp Foster, Japan increased from an initial cost estimate in fiscal year 2012 of $79 million to $107 million in fiscal year 2014 (or a 35-percent increase). As detailed on the fiscal year 2014 reprogramming request, the Department of Defense Education Activity attributed the increased cost to the volatile construction climate in Japan caused by natural disasters; Japanese government policies, economic stimulus, and reform; and the planned developments for the 2020 Tokyo Olympic Games. Although this project is not owned by any of the military departments, it is being managed by the Army Corps of Engineers in its role as a DOD construction agent through which it plays an important role in the development of the construction cost estimate. The Department of Defense Education Activity is the project owner and the Army Corps of Engineers is the construction agent. To determine the reliability of the cost estimates for these three selected projects, we assessed the cost estimates against the best practices for developing a reliable estimate in our Cost Guide. As previously discussed, the Cost Guide defines the four characteristics— comprehensive, well documented, accurate, and credible—of a reliable cost estimate and the associated best practices related to each characteristic. In conducting these assessments, we examined both the Form 1391 estimate (i.e., the estimate used to develop the budget) and the independent government estimate i.e., (the estimate used to award the contract) for each project. Our analysis of the cost estimates for the three selected projects shows that the cost estimators did not follow all the best practices listed for each of the four characteristics. As a result, none of the characteristics were fully or substantially met. To be reliable, a cost estimate must substantially or fully meet each of the four characteristics. As the Cost Guide states, if any of the characteristics are not met, minimally met, or partially met, then the cost estimate does not fully reflect the characteristics of a high-quality estimate and cannot be considered reliable. Table 7 provides the results of our assessment of the cost estimates for each of the three selected projects. The Cost Guide also identifies 12 steps that, when incorporated into an agency’s cost estimating procedures and guidance, are more likely to result in reliable and valid cost estimates. However, our analysis of DOD’s department-wide cost estimating guidance—the Unified Facilities Criteria—found that the criteria did not include all of these 12 steps. The Unified Facilities Criteria incorporates some of the 12 steps to some degree, but not others, and as a result DOD is at a greater risk of developing estimates that are not reliable. Table 8 provides our assessment of the extent to which DOD’s Unified Facilities Criteria incorporates the 12 steps needed to develop a high-quality, reliable cost estimate. Each of the military departments is required to follow the Unified Facilities Criteria to the greatest extent possible when designing and constructing facilities. However, as shown by the table above, there are shortcomings in these criteria when compared with our Cost Guide. Despite these shortcomings, the military departments have gone beyond the Unified Facilities Criteria and developed their own guidance that more closely aligns with our Cost Guide. For example, for both the “determining the estimating structure” and “obtain the data” steps, we found that all three military departments had developed their own guidance that more closely aligned with the 12 steps than the Unified Criteria did. In addition, some military departments are also making improvements to their cost estimating processes, but these improvements have not been fully implemented yet. For example, the Air Force Civil Engineer Center is implementing a cost estimate improvement plan to include the training of nearly 700 airmen and has conducted a study that directly ties the 12 steps in the Cost Guide to the associated tasks to be completed by the Air Force cost estimator to meet each individual step. However, the actions contained in the cost improvement plan have not been fully implemented and still remain in the concept phase. Similarly, although the Army Corps of Engineers is investigating expanding the use the of cost and schedule risk analysis—which could align with the best practices in the Cost Guide—that the Army currently conducts for selected civil work construction projects to its high-cost military construction projects, the Army has not formally required the use of these tools. In appendix IV, we describe the guidance the military departments have developed beyond the Unified Facilities Criteria. The Cost Guide is designed to establish a consistent methodology that is based on best practices and that can be used across the federal government for developing, managing, and evaluating capital program cost estimates. Air Force and Army Corps of Engineers officials noted that there may be instances in which following all the 12 steps of the Cost Guide for every MILCON project would not be appropriate to the risk level of the project. For example, it may not be realistic or to the military departments’ benefit for the military departments to conduct a sensitivity and uncertainty analysis or develop an independent cost estimate for all the construction projects they initiate every year, especially for low-cost projects. We agree that it may not be suitable to fully apply all 12 of the cost estimating steps in the Cost Guide to all MILCON projects. However, incorporating the 12 steps into the Unified Facilities Criteria would establish consistency across DOD in the cost estimating process by ensuring that, for each MILCON project, each step in the Cost Guide would at least be considered. Furthermore, DOD could choose to establish thresholds—based on, for example, the dollar values of the projects—to guide the services in implementing the 12 steps for the most valuable projects. Skipping or not considering any step of the 12-step cost estimating process, especially for high-value projects such as those in our case studies, increases the risk that cost estimates may use improper assumptions, lack appropriate definition, or be otherwise unreliable. Without improving the Unified Facilities Criteria with respect to cost estimating processes, DOD and the services will not be positioned well to provide reliable cost estimates to DOD and congressional decision- makers. Each year DOD receives billions of dollars in MILCON appropriations to use for projects in the United States and overseas. The quality of project cost estimates are of great importance since those estimates are the basis for DOD’s requests for appropriations. While DOD’s policy is that MILCON cost estimates be prepared as accurately as possible in order to reflect the full cost of constructing DOD facilities, DOD’s Unified Facilities Criteria—the department’s primary construction criteria for developing cost estimates—does not fully incorporate all of the steps needed for producing reliable cost estimates. Until DOD incorporates the 12 steps of high-quality, reliable cost estimating into this department-wide construction criteria, DOD and congressional decision-makers may not have reliable estimates to inform their decisions regarding appropriations and the oversight of projects. We are making one recommendation to DOD: The Secretary of Defense should ensure that the Assistant Secretary of Defense for Energy, Installations, and the Environment work with DOD’s construction agents, military departments, and other offices to improve DOD’s MILCON cost estimating guidance (i.e., DOD’s Unified Facilities Criteria) by fully incorporating all the steps needed for developing high- quality reliable cost estimates. (Recommendation 1) We provided a draft of this report to DOD. In written comments, which are reprinted in their entirety in appendix VI, DOD partially concurred with our recommendation. DOD also provided technical comments that have been incorporated into the report as appropriate. DOD partially concurred with our recommendation to improve its cost estimating guidance by fully incorporating all 12 steps needed for developing high-quality, reliable estimates. DOD stated that it did not believe that it is suitable to fully apply all 12 steps to any construction project due to characteristics of the military construction program that DOD believes differ from those of major system or weapon acquisition programs. However, DOD also stated that it concurred with the intent and general applicability of the twelve steps to military construction and that DOD cost estimating guidance lacks specificity in several of these areas. DOD acknowledged that expanding its cost guidance to more fully incorporate these steps would benefit the military construction program, and that it is planning to address this by revising its cost guidance during Fiscal Year 2019. In our report, we recognize that it may not be appropriate to fully apply all 12 steps to each construction project. For example, it may not be realistic or to the military departments’ benefit to conduct a sensitivity and uncertainty analysis or develop an independent cost estimate for all the construction projects they initiate every year, especially for low-cost projects. Accordingly, we did not recommend that DOD fully apply all 12 steps to each construction project, but rather that it fully incorporate the 12 steps into the Unified Facilities Criteria so that, at least, each step is considered for each project. DOD could then choose to establish thresholds—based on, for example, the dollar values of the projects—to determine for which the 12 steps should be fully applied or other circumstances in which some steps might not be applicable. We believe DOD’s planned revisions will meet the general intent of our recommendation. We are sending copies of this report to the appropriate congressional committees; the Secretary of Defense, the Secretaries of the Army, Navy, and Air Force. In addition, the report is available at no charge on the GAO website at http://www.gao.gov. If you or your staff has any questions about this report, please contact me at (202) 512-4523 or leporeb@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made key contributions to this report are listed in appendix VI. To examine the active component’s military construction (MILCON) obligations and expended balances, we reviewed MILCON appropriations found in appropriations acts, including accompanying explanatory statements and conference committee reports from fiscal year 2005 through 2016. Further, we analyzed the obligation and disbursement data of the active component‘s MILCON accounts, appropriation status reports, bid savings reports, as well as annual reports from the U.S. Department of the Treasury. We also collected and compared project data from each of the active component on projects that had been initiated and completed during fiscal year 2010 through fiscal year 2016. Specifically, we compared the initial estimate as shown on the Form 1391—the form DOD uses to submit requirements and justifications in support of its funding requests to Congress—with the contract award amount and analyzed any differences between the two. To examine the amount of MILCON reprogramming during fiscal years 2010 and 2016 by the active component, we reviewed DOD’s requests to Congress to reprogram MILCON funds from one project to another. We calculated the total number of times such requests were made and the dollar amounts for fiscal year 2010 through fiscal year 2016. We selected this time frame because the reprogramming requests were readily available from DOD. In addition, we judgmentally selected three projects from this same time frame and reviewed accompanying Forms 1391 and the reprogramming requests associated with the projects to illustrate instances in which savings from one MILCON project funded another project. We collected and analyzed data for fiscal years 2005 through 2016 on the active component MILCON appropriations, obligations, and disbursements and we collected reprogramming data for fiscal years 2010 through 2016. We assessed the reliability of the data by interviewing knowledgeable officials about the data and the steps that they had taken to verify the data’s accuracy. We determined that the data were sufficiently reliable for our objectives. To determine the extent to which DOD’s MILCON cost estimates are reliable and DOD’s guidance for producing estimates fully incorporates all of the steps needed for developing reliable estimates, we compared the process for developing three selected projects with the characteristics and best practices for developing a reliable estimate identified in GAO’s Cost Estimating and Assessment Guide: Best Practices for Developing and Managing Capital Program Costs (the Cost Guide). This guide is a compilation of cost estimating best practices drawn from across industry and federal government. We selected our projects from the universe of projects that we reasonably expected could have begun execution (i.e., projects initiated during fiscal years 2012-2014); projects that were underway, but not substantially completed (i.e., between 10- and 75- percent complete); and projects that constituted a significant financial investment (i.e., projects with appropriations of $75 million or greater). Ultimately, of 690 total projects we identified DOD-wide, 13 met these criteria and, from this sample, we selected the 3 projects included in this report: (1) the construction of a replacement elementary school at Camp Foster, Japan; (2) the construction of a Strategic Command operations building at Offutt Air Force Base, Nebraska; and (3) the construction of a Marine Corps command headquarters and cyberspace operations building in Fort Meade, Maryland. In conducting the assessments for these three selected projects, we examined the processes used to develop both the Form 1391 estimate (i.e the form DOD uses to submit project-level requirements and justifications in support of its MILCON funding requests to Congress ) and the independent government estimate (i.e., the estimate used to award the contract) to determine whether the project cost estimates had the characteristics of a high-quality and reliable cost estimate, as defined in the Cost Guide. These projects are not intended to be a projectable sample, but to illustrate how cost estimates are assessed against best practices. Although the Camp Foster project is not owned by any of the active component, the construction and planning of the project is being led by the Army Corps of Engineers in its capacity as a DOD construction agent and, as such, we decided to include it in our review. Additionally, we reviewed DOD’s Unified Facilities Criteria and the active component’s respective guidance related to MILCON cost estimating and compared them with the steps needed for developing reliable estimates identified in the Cost Guide. We also interviewed military project cost estimators and active component construction agents to discuss the requirements and guidance they follow in preparing, documenting, and reviewing project cost estimates. Table 9 details the documents we reviewed for our cost estimating assessments. We conducted this performance audit from January 2016 to March 2018 in accordance with generally accepted government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. In this appendix we provide the supporting details on the active component’s unobligated and unexpended balances of military construction (MILCON) appropriations for fiscal years 2005 through 2016. We include details on unobligated and unexpended balances by appropriation year and include individual tables for each military department of the active component. Overall, the active component had high obligation and expenditure rates associated with MILCON appropriations that have expired or been canceled. The Army, the Air Force, and the Navy consistently expended over 90 percent of amounts appropriated in fiscal years 2005 through 2011. This appendix also provides supporting details on the active component’s execution of MILCON appropriations for fiscal years 2010 through 2016. Using Department of Defense (DOD) data, we identified two groups of MILCON projects: congressionally directed and other. “Congressionally directed” projects are those MILCON projects specifically identified in an appropriation act, explanatory statement, and/or committee reports accompanying the appropriation act for a specific fiscal year. “Other” projects refer to congressionally directed MILCON projects identified in an appropriation act, explanatory statement, and/or conference committee reports in a previous fiscal year. Overall, the active component obligated about 89 percent of its fiscal years 2010 through 2012 appropriations for congressionally directed projects whose appropriations expired on September 30, 2017. Tables 10 through 12 present detailed information on unexpended and unobligated balances for each military department of the active component’s MILCON appropriation for fiscal years 2005 through 2016, as reported by DOD as of September 30, 2016. Table 10 shows that for fiscal years 2005 through 2012, the Army expended almost all of its MILCON appropriations. Specifically, with the exception of fiscal year 2012, the Army expended at least 90 percent of its appropriations received each fiscal year for 2005 through 2011. Unexpended rates for amounts appropriated for fiscal years 2014 through 2016 vary and unobligated amounts for these years remain available for new obligations. Table 11 shows that, for fiscal years 2005 through 2013, the Air Force expended almost all of its MILCON appropriations. Specifically, the Air Force expended at least 95 percent of its appropriations received each year for fiscal years 2005 through 2011 and also in fiscal year 2013. Unexpended rates for amounts appropriated for fiscal years 2014 through 2016 vary and unobligated amounts for these years remain available for new obligations. Table 12 shows that for fiscal years 2005 through 2012, the Navy expended almost all of its MILCON appropriations. Specifically, the Navy expended at least 90 percent of its appropriations received each fiscal year for 2005 through 2011. Unexpended rates for amounts appropriated for fiscal years 2014 through 2016 vary and unobligated amounts for these years remain available for new obligations. Tables 13 through 15 provide detailed information on budget execution for each active duty military department’s MILCON appropriation for “congressionally directed” and “other” MILCON projects for fiscal years 2010 through 2016, as reported by DOD as of September 30, 2016. Table13 shows the obligations made by the Army for MILCON appropriations for fiscal years 2010 through 2016. We analyzed the obligations made during these appropriations’ period of availability for congressionally directed and other MILCON projects. For fiscal year 2010, using data in the table, we found that about 97.2 percent of obligations were for congressionally directed projects and 2.8 percent were for other projects, as discussed above. In fiscal year 2011, about 94 percent of obligations were for congressionally directed projects and 4.2 percent were for other projects; and in fiscal year 2012, about 86.5 percent of obligations were for congressionally directed projects and 7.2 percent were for other projects. Table 14 shows the obligations made by the Air Force for MILCON appropriations for fiscal years 2010 through 2016. We analyzed the obligations made during these appropriations’ period of availability for congressionally directed and other MILCON projects. For fiscal year 2010, using the data listed in the table, we found that 90.5 percent of obligations were for congressionally directed projects and 7.3 percent were for other projects, as discussed above. In fiscal year 2011, about 84.3 percent of obligations were for congressionally directed projects and 12.9 percent were for other projects; and in fiscal year 2012, about 87.5 percent of obligations were for congressionally directed projects and 9.0 percent were for other projects. Table 15 shows the obligations made by the Navy for MILCON appropriations for fiscal years 2010 through 2016. We analyzed the obligations made during these appropriations’ period of availability for congressionally directed and other MILCON projects. For fiscal year 2010, using data in the table, we found that 84.7 percent of obligations were for congressionally directed projects and 15.0 percent were for other projects, as discussed above. In fiscal year 2011, about 87.7 percent of obligations were for congressionally directed projects and 11.8 percent were for other projects; and in fiscal year 2012, about 85.5 percent of obligations were for congressionally directed projects and 13.4 percent for other projects. This appendix provides information on our analysis of DOD’s estimated initial costs and contract award amounts of projects that had been initiated and completed during fiscal year 2010 through fiscal year 2016 by the active component. An official from the Office of the Assistant Secretary of Defense for Energy, Installations, and Environment told us that, to determine whether initial cost estimates were over- or underestimated, a comparison between initial Form 1391 estimates and contract award amounts would be a valid approach since contract award amounts are, in general, estimates of the same requirements identified on a Form 1391. The official also noted that supervision, inspection, overhead, and contingency costs included on a Form 1391 are not included in contract award amounts, which could create differences between the Form 1391 cost estimates and contract award prices. Because of this, we excluded the supervision, inspection, overhead, and contingency costs from the Form 1391 estimates in the table below to eliminate those differences. Form 1391 cost estimates may also vary from contract award amounts for reasons such as changes in project size or scope, changes in project characteristics, unexpectedly high or low contractor bids, or differences in expected building material costs, among other things. A negative percent change from the Form 1391 estimate to the contract award amount indicates the estimated project cost was overestimated and a positive percent change indicates the project was underestimated. We did not determine the precise reasons for any differences between estimated costs and contract award amounts. Table 16 lists information on 414 completed projects funded with military construction (MILCON) appropriations during fiscal year 2010 through fiscal year 2016 sorted by largest percentage overestimated to largest percentage underestimated. The military departments of the active component have gone beyond the Unified Facilities Criteria and developed their own guidance for military construction (MILCON) that more closely aligns with the 12 steps needed for developing high-quality, reliable estimates. Table 17 describes the guidance developed by the military departments to align with those steps. In addition to the contact named above, Maria Storts, Assistant Director; Bonita Anderson; Shawn Arbogast; Ronald Bergman; Brian Bothwell; Robert Brown; Farrah Graham; Mae Jones; Jennifer Leotta; Amie Lesser; Felicia Lopez; Carol Petersen; Vikki Porter; Steve Pruitt; and Karen Richey made key contributions to this report.

Answer: Between fiscal years 2005 and 2016, Congress annually appropriated between $2.5 to $9.6 billion in MILCON funding for the active component of the U.S. military to use for projects worldwide. Reliable project construction cost estimates are of great importance, since those estimates drive these appropriations. House Report 114-537 accompanying a proposed bill authorizing national defense activities for fiscal year 2017 included a provision for GAO to report on DOD's MILCON cost estimating. This report examines the extent to which (1) the active component obligated and expended the MILCON appropriations received during fiscal years 2005-2016, (2) the active component reprogrammed MILCON appropriations during fiscal years 2010 through 2016, and (3) DOD's MILCON cost estimates are reliable for selected projects and DOD's guidance for developing estimates fully incorporates the steps needed for developing reliable estimates. GAO analyzed the active components' MILCON execution data and reviewed DOD's guidance for cost estimating and compared it with the best practices identified in GAO's Cost Estimating and Assessment Guide . During fiscal years 2005 through 2016, Congress appropriated about $66 billion in military construction funds (MILCON) to the active duty Army, Navy, and Air Force (referred to as the active component) for projects. As of September 30, 2016, the active component had obligated all but about $5.1 billion and expended all but about $11 billion of those funds. Of the $5.1 billion remaining unobligated, about $4.6 billion was still available to be obligated because MILCON appropriations are generally available for new obligations for 5 years. According to Department of Defense (DOD) officials, available but unobligated amounts no longer needed may be either taken back by Congress or reprogrammed to other MILCON projects that the active component identifies as needing additional funding. During fiscal years 2010 through 2016, the active component reprogrammed about $1.6 billion in MILCON appropriations to fund emergency projects, projects that were authorized but did not receive specific appropriations, and projects needing additional funding. Of this amount, the Army reprogrammed about $789 million; the Navy, about $535 million; and the Air Force, about $295 million. DOD's guidance does not fully incorporate the steps needed for developing reliable estimates and the estimates for three projects that GAO reviewed were not reliable. Specifically, two of the three high-value projects GAO examined experienced a more than 30-percent increase from the initial cost estimates submitted to Congress. GAO determined that DOD cost estimators did not follow all the best practices associated with the four characteristics—comprehensive, well-documented, accurate, and credible—of a reliable estimate for these projects. GAO's Cost Estimating and Assessment Guide identifies 12 steps that, if used, are more likely to result in reliable and valid cost estimates. However, as shown below, DOD's construction guidance—the Unified Facilities Criteria—does not include all of these steps. Until DOD incorporates these steps, DOD and congressional decision-makers may not have reliable estimates to inform their decisions regarding appropriations and the oversight of projects. GAO recommends that DOD ensure that its cost estimating guidance fully incorporate the steps needed for developing reliable cost estimates. DOD partially concurred with GAO's recommendation and stated that it will issue revised cost guidance in fiscal year 2019 that more fully incorporates those steps that would benefit the military construction program.