The first BRAC Commission was chartered by the Secretary of Defense in 1988, and operated in accordance with processes later established by the Defense Authorization Amendments and Base Closure and Realignment Act of 1988. Since that time, the BRAC process has changed in many ways, with a variety of requirements and procedures mandated by subsequent BRAC statutes or adopted by DOD. Among these is the requirement that the Secretary of Defense develop a current force structure plan. DOD’s force structure plan is designed to identify the number and type of forces that DOD needs to combat the anticipated threats to the security of the United States. As specified in DOD’s force structure plan in support of BRAC 2005, the President’s National Security Strategy and the Secretary of Defense’s National Defense Strategy provide the focus for the military forces. DOD then analyzes current and future threats, challenges, and opportunities to develop the force structure plan. DOD’s planning framework helps determine the capabilities required to respond to a range of scenarios. The Department then analyzes the force requirements for the most likely, the most dangerous, and the most demanding circumstances. One of the objectives of the first BRAC Commission was to review the current and planned military base structure in light of force structure assumptions and, using the process and the criteria the Commission developed, to identify which bases should be realigned or closed. To accomplish this, the Commission used a two-phase approach. Phase I grouped bases into 22 overall categories, such as training bases and administrative headquarters, and then focused on determining the military value of bases within each category, each base’s capacity to absorb additional missions and forces, and the overall excess capacity within the category. The Commission then ranked the bases to identify those warranting review in phase II, which focused on assessing the cost and savings of base realignment and closure options. The Defense Base Realignment and Closure Act of 1990 substantially revised the process for DOD base closure and realignment actions within the United States, establishing an independent Defense Base Closure and Realignment Commission and providing for BRAC rounds in 1991, 1993, and 1995. One of the key elements of the 1990 BRAC statute was the requirement that DOD submit a force structure plan and that closure and realignment decisions be based on that force structure plan and on the final selection criteria established for the BRAC round. As part of the BRAC process for 1991, 1993, and 1995, an important step in the military services’ approach for identifying bases to close or realign was determining whether excess capacity existed at their bases. The starting point for this step was comparing changes in the force structure plan to the base structure of the military services. After applying military value criteria and other specific BRAC criteria, each of the services developed their recommendations for closures and realignments for submission to the BRAC Commission. In May 1997, the Secretary of Defense announced his intention to ask Congress to authorize two additional BRAC rounds. Later that year, Congress enacted section 2824 of the National Defense Authorization Act for Fiscal Year 1998, which required that the Secretary of Defense provide the congressional defense committees with a comprehensive report on a range of BRAC issues, including the need for any additional BRAC rounds and an estimate of the amount of DOD’s excess capacity. DOD submitted the required report in April 1998 and estimated that DOD had 23 percent excess capacity. In the report, DOD also stated that its method for estimating excess capacity determined the extent to which reductions in base structure had kept pace with reductions in force structure since 1989. The National Defense Authorization Act for Fiscal Year 2002 amended the 1990 BRAC statute by authorizing a BRAC round for 2005, and required DOD to report to Congress on several BRAC-related issues in 2004 in order for the 2005 round to proceed. The statute directed, among other things, that the Secretary of Defense provide Congress with a 20- year force structure plan and a worldwide inventory of military installations and facilities as part of DOD’s fiscal year 2005 budget justification documents. In addition, as part of the force structure plan and inventory submission, the Secretary was to prepare (1) a description of the infrastructure necessary to support the force structure described in the force-structure plan, (2) a discussion of categories of excess infrastructure and infrastructure capacity, and (3) an economic analysis of the effect of the closure or realignment of military installations to reduce excess infrastructure. DOD provided the required report, which estimated that the department had 24 percent excess capacity, on March 23, 2004. In that report, the Secretary of Defense also certified that an additional round of BRAC was needed and that the round would result in savings by fiscal year 2011. Subsequently, an initial part of DOD’s BRAC recommendations development process for the 2005 round involved an overall capacity analysis of specific locations or functions and subfunctions at specific locations. The analysis relied on data calls to obtain certified data to assess such factors as maximum potential capacity, current capacity, current usage, excess capacity, and capacity needed to meet surge requirements. This capacity analysis—in conjunction with the department’s 20-year force structure plan, military value analysis, and transformational options; applicable guiding principles, objectives, or policy imperatives identified by individual military services or joint cross- service groups; and military judgment—was used to identify realignment and closure scenarios for further analysis, ultimately leading to finalized recommendations for base realignments and closures. Our review of DOD’s pre-BRAC estimates of excess capacity found that the methods DOD has used and the resulting estimates have limitations. DOD used similar methods in 1998 and 2004 to calculate its pre-BRAC estimates of excess capacity. However, our current review identified a number of additional limitations with DOD’s methods. For example, DOD’s approach assigns each installation to only one mission category, even though most installations support more than one mission. In addition, to arrive at the excess capacity estimate it provided to Congress in 2012 and repeated in 2013, DOD subtracted an estimate of excess capacity that it expected would be disposed of during the 2005 BRAC round from the amount of excess capacity estimated to exist immediately before that BRAC round to arrive at the current excess capacity estimate of about 20 percent. However, because DOD’s pre-BRAC excess capacity estimate, expressed as a percentage of bases, and plant replacement value, expressed in dollars, are not measured in the same units, they are not comparable measures. DOD based its 1998 and 2004 estimates of 23 percent and 24 percent excess capacity, respectively, on a method that compared measures of force structure projected to be in place at the end of the 5-year Future Years Defense Programs that were current at the time of each estimate, to associated indicators of capacity. DOD’s 1998 and 2004 technique consisted of three major steps: (1) categorizing bases according to their primary missions and defining indicators of capacity, (2) developing ratios of capacity-to-force structure for DOD’s baseline year of 1989, and (3) aggregating these various excess capacity indicators that were calculated at the installation level to the military service level and then department- wide. To begin DOD’s analysis, each of the military services identified categories for their bases, identified bases that the services considered major installations, and categorized their bases according to their primary missions—such as depots, training, or administration—so that each installation was included in only one category. Figure 1 shows the installation categories used by each military service and the Defense Logistics Agency. Figure 1. Installation Categories for the Military Services and the Defense Logistics Agency. The services then defined various indicators of capacity—such as maneuver base acres or facility square feet—for each installation category. Next, DOD divided each services’ indicators of capacity by a measure of force structure—such as the number of military and civilian personnel authorized, authorized end strength, or the size of the acquisition workforce—to develop ratios of capacity-to-projected force structure and compared them to ratios from 1989, which was used as a baseline. For its 1998 analysis DOD projected force structure through 2003, and for its 2004 analysis DOD projected force structure through 2009 because these dates marked the end of DOD’s Future Year’s Defense Program projections that were current at the time the analyses were performed. For example, as illustrated in Figure 2, in its 1998 capacity analysis, DOD projected, that in 2003, there would be 6.575 million square feet of administrative space on Army administrative bases, and DOD projected that there would be 65,516 military and civilian personnel assigned to those bases, resulting in a capacity-to-force structure ratio of 100.4. Similarly, according to its 2004 capacity analysis, DOD projected that, in 2009, there would be 6.121 million square feet of administrative space on Army administrative bases, and DOD projected that there would be 64,598 military and civilian personnel assigned to those bases, resulting in a capacity-to-force structure ratio of 94.8. DOD then calculated the extent to which the ratio of capacity-to-force structure for each base category differed from the ratio in 1989, which was used as a baseline. To do this, DOD first calculated an estimate of capacity it would need for the year in question for each of its various indicators of capacity. For instance, to continue with the second example above, DOD calculated an estimate of administrative capacity the Army would need for 2009. As illustrated in Figure 3, DOD calculated its needed capacity indicators by multiplying the projected 2009 force structure measure (64,598 military and civilian personnel in this case) by the 1989 capacity-to-force ratio (81.3 for Army administrative bases), which in this case resulted in an estimated needed capacity of 5.25 million square feet of Army administrative space. To calculate the projected excess capacity for 2009, DOD subtracted a base category’s estimated needed capacity from its projected 2009 capacity.