During Operation Desert Storm, the Army deployed all or nearly all of certain support units such as transportation and military police units. As threats to U.S. security interests evolve and defense budgets shrink, it is important that the Army accurately identify the support forces it requires. TAA is the Army’s biennial process to determine required support units and recommend the type and number of support units that the Army should include in its budget. The requirements generated in this process are dependent on a variety of inputs and guidance, including scenarios derived from the Defense Planning Guidance, wargaming assumptions, and logistical data that are developed for use in the computer modeling. For purposes of this report, logistical data include planning factors, consumption rates, and other data. Planning factors cover 9 of the Department of Defense’s (DOD) 10 classes of supply; for modeling purposes, these factors are usually expressed in pounds per person per day. Consumption rates include such factors as the number of soldiers admitted to a hospital per day and the number of prisoners captured per day. An example of other logistical data would be the amount of support that allies can provide to offset U.S. requirements. While planning scenarios are largely given to the Army, logistical data must be developed by the Army. These data are compiled in the Army Force Planning Data and Assumptions document (AFPDA). Once the data are finalized—during TAA force structure conferences—the Concepts Analysis Agency conducts the computer modeling, which generates unit requirements based on a set of rules that determine the number of support units needed. After requirements are determined, additional force structure conferences are held where Army officials decide which units can be filled within the projected resource levels. Figure 1 highlights key elements of the TAA process for developing requirements and making force resourcing decisions. The Army’s Deputy Chief of Staff for Logistics (DCSLOG) is responsible for developing the logistics data in the AFPDA. In practice, some of this responsibility has been delegated to the Combined Arms Support Command (CASCOM), which is the Army’s integrator for some combat service support issues. Biennially, DCSLOG and CASCOM update the logistics portions of the AFPDA by tasking the major commands, Army component commands, and schools to validate the logistical data related to their areas of expertise. For example, school representatives are tasked to validate data based on their perspectives on doctrine; component commands are tasked to provide their perspectives on unique data and issues related to their theater. The logistical data are presented to workshops to gain group acceptance. They are then sent forward to the TAA force structure conference, where the data are approved. Army documents describe the AFPDA update as a systematic review and validation of key data used in TAA. However, Army regulations related to TAA primarily focused on the validation and management of planning factors. Effective May 1994, the Army broadened its regulation to include additional logistical data found in the AFPDA. This change should help to improve the validity of logistical data, but additional procedures are needed to correct the problems we found with the AFPDA update process. Before May 1994, Army regulation 700-8 specified responsibilities for the development and management of logistics planning factors. The Army Logistics Center, CASCOM’s predecessor, was responsible for managing the development, validation, and collection of planning factors, and was to recommend factors to DCSLOG for approval. However, DCSLOG and CASCOM officials did not believe that the development and management of other logistical data for use in the AFPDA, such as theater specific data provided by component commanders, were covered in this or any other regulation prior to May 1994. In 1993, the Army Audit Agency found the Army’s management of planning factors to be inadequate, and recommended changes to the process. The recommended changes included tasking responsible activities to (1) update planning factors periodically and (2) validate methodologies and assumptions used to develop planning factors. In 1994, the Army revised its regulations to improve the management of planning factors. These revisions included specifying time frames for updates to take place and incorporating internal control responsibilities to guide the development of planning factors. The regulation was also changed to include other logistical data and to link the development of logistical data to the AFPDA. While the regulation gave DCSLOG the overall responsibility for logistical data management, the day-to-day management for logistical data was delegated to CASCOM. The Army’s TAA process relied heavily on commands and schools to review and validate the accuracy of logistics data. Commands and schools were requested prior to the TAA workshops to review and validate logistics data. However, we found that some data had not been validated, were outdated, or were not supported by documented studies. Because the process was poorly documented, we could not determine how widespread these problems were. Further, no organization was responsible for ensuring that the data validations occurred and were derived from consistent and sound methodological studies. Our review of available documentation for several past TAAs showed that some data had not been validated in several years. Although some school officials believed the AFPDA contained outdated data, actions were not undertaken to validate or change the data. For instance, officials with the ordnance school, which develops doctrine for maintenance units, expressed concern in 1989 that rates for equipment that is expected to be abandoned and the rates for vehicles expected to be damaged in combat had not been updated in 4 years and, thus, were unlikely to be accurate. These rates primarily affect the number of maintenance units. In another instance, the Army engineers submitted workload factors that were outdated and had not been validated prior to the January 1992 TAA workshop. These factors measured the number of hours it takes to construct such structures as railroads, bridges, and pipelines. A new study was done only after concerns were raised about the validity of these factors during the AFPDA workshops. We found data that were not supported by documentation. At the U.S. Army Central Command (ARCENT), for example, officials that provided data for TAA in 1992 had not maintained documentation that would show how the data were developed. This lack of documentation reduces assurance that the data are valid and can cause problems during future updates if key personnel change. For example, U.S. Army, Korea, officials told us that they did not know how data on the Korean theater had been developed because there were no files or individuals who could explain the prior year’s validation process. We found that while the Army sought consistency and accuracy in the logistical data update process, no organization ensured that a reasonable methodology was used by the commands and schools nor that studies or supporting models used to develop the data were valid. We found that neither CASCOM nor DCSLOG had overseen the validation process. According to a DCSLOG official, DCSLOG has not routinely reviewed the methodology used by various proponents who submit factors and data to the process. This official stated that only if a factor looked unusual would it generate an inquiry back to the proponent to ask how that factor was developed. CASCOM officials stated that they had no regulatory requirement to review the methodology of proponents who developed logistical data. The Army’s revised regulation governing the development and validation of logistical data for the TAA process is an improvement. The revised regulation requires CASCOM to examine the AFPDA to ensure data consistency, adherence to doctrine, necessity, identification of sources, and rationale of methodology. It also specifies time frames for the AFPDA updates, thus putting the commands and schools on notice when the data validation will be required. CASCOM officials stated that they have not yet defined their role regarding overseeing the update of AFPDA data. Therefore, CASCOM had not told the commands and schools what will be required of them. We believe that CASCOM should establish procedures that would specify how commands and schools are to validate and maintain all logistical data in the AFPDA. Specifically, major commands, Army component commands, and schools should be directed to ensure that their data are based on sound analytical studies and assumptions and that the methodological bases for those data and assumptions are documented. Moreover, CASCOM’s guidance should specify what CASCOM will require from commands and schools to exercise its oversight responsibility. According to DOD, CASCOM is already developing procedures to improve the update process and should complete a review of the adequacy of existing data by the end of 1996. According to Army regulations, theater-specific data are best obtained from Army components most familiar with the region and involved in the theater war-planning process. However, we found that the current level of participation by Army component commanders does not ensure that data and assumptions used by TAA are similar to data that component commands use to develop their war plans. The result is that the required force structure developed in TAA does not agree with theater war plans. Army component commands should have an important role in the TAA process. During development of the AFPDA, Army regulations instruct the Army components to review, revalidate, and submit theater-unique logistics data. Specifically, they are to provide data such as support provided by allies, theater stockage policies, and theater consumption factors. Also, as part of the TAA process, Army components identify theater-unique requirements that may be different from current doctrinal rules. This identification is required because the Army recognizes that each theater is unique and that the Army component commands are the most familiar with their area. In practice, however, Army components sometimes believe that their role in the process is insufficient to affect the process. Thus, Army component officials said they don’t always consider developing data for TAA as a priority. Therefore, some commands do not always send representatives to workshops where data are discussed and adopted. In other instances, component command representatives at the workshops have not challenged data that is inconsistent with their plans. TAA requirements for military theaters sometimes differ from those in theater war plans.