Friendly fire is a serious problem confronting DOD and the military services. According to a report issued by the Office of Technology Assessment in 1993, about 24 percent of the fatalities experienced during Operation Desert Storm were the result of friendly fire—a rate that appeared very high compared to past conflicts. Sixty-one percent of these incidents involved ground-to-ground incidents, while air-to-ground and ground-to-air incidents accounted for 36 and 3 percent, respectively. A more recent notable incident is the 1994 friendly forces’ shootdown of two Blackhawk helicopters over Iraq during Operation Provide Comfort. Such incidents may be caused by command and control failures, navigation failures, or target misidentification. A key aspect of DOD’s effort to prevent friendly fire is the development of new combat identification systems. Some of these systems will “cooperate” to identify friendly targets through queries and answers. Others will identify targets as friendly or unknown with the help of data sources, such as radio emissions or acoustic signals. And others, known as situational awareness systems, will rely on periodic updates of position data to help users locate friendly forces. The cost of such systems is significant. For example, the Army’s efforts to develop, field, and maintain cooperative combat identification systems alone are expected to cost more than $1 billion. Successfully developing and implementing these systems is a major challenge for DOD. The systems themselves will be developed and managed by many different entities within DOD and the military services. They will be involved in a wide range of military operations and installed on a broad array of equipment. At the same time, however, these systems will need to be compatible and interoperable. They will also need to fit in with DOD’s long-term goals for achieving information superiority over the enemy. DOD defines this as “the capability to collect, process, and disseminate an uninterrupted flow of information while exploiting or denying an adversary’s ability to do the same.” Additionally, it is important that these systems be able to work with systems belonging to North Atlantic Treaty Organization (NATO) and other allies in order to help preclude friendly fire incidents during coalition operations. DOD does not yet have a complete enterprise architecture to guide its efforts to develop a family of combat identification systems and past attempts to establish an architecture were not comprehensive or adopted by the services. Without a “blueprint” to guide and constrain DOD’s investments in combat identification systems, the military services and Defense agencies may well find themselves with combat identification systems that are duplicative, not interoperable, and unnecessarily costly to maintain and interface. An enterprise architecture systematically captures in useful models, diagrams, and narrative the full breadth and depth of the mission-based mode of operations for a given enterprise, which can be (1) a single organization or (2) a functional or mission area that transcends more than one organizational boundary (e.g., financial management, acquisition management, or combat identification). Further, such an architecture describes the enterprise’s operations in both (1) logical terms, such as interrelated functions, information needs and flows, work locations, and system applications, and (2) technical terms, such as hardware, software, data, communications, and security attributes and performance standards. If defined properly, enterprise architectures can assist in optimizing interdependencies and interrelationships among an organization’s operations and the underlying technology supporting these operations. Our experience with federal agencies has shown that attempting to define and build major systems without first completing an enterprise systems architecture often results in systems that are duplicative, not well integrated, unnecessarily costly to maintain and interface, and do not effectively optimize mission performance. The Office of Management and Budget (OMB) has recognized the importance of agency enterprise architectures. OMB has issued guidance that, among other things, requires agency information system investments to be consistent with agency architectures. More recently, the Chief Information Officers Council produced guidance for federal agencies in initiating, developing, using, and maintaining enterprise architectures. DOD has also issued architecture policy, including a framework defining an architecture’s structure and content. Specifically, in February 1998,DOD directed its components and activities to use the Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) Architecture Framework, Version 2.0. DOD’s framework is comprised of three components: (1) an operational architecture—that is, the operational elements, activities, tasks, and information flows required to accomplish or support a mission, (2) a systems architecture—that is, the systems and interconnections supporting the functional mission, and (3) a technical architecture—that is, the minimum set of standards and rules governing the arrangement, interaction, and interdependence of systems applications and infrastructure. According to DOD, the C4ISR Architecture Framework is a critical tool for achieving its strategic direction and all DOD components and activities should use the framework for all functional areas and domains within the Department. The C4ISR Architecture Framework is recognized in the Federal Chief Information Officers Council’s A Practical Guide to Federal Enterprise Architecture as a model architecture framework for developing enterprise architectures. Appendix I provides more detailed information on the C4ISR Architecture Framework. DOD has also recognized the importance of architectures in its recently revised acquisition guidance, DOD Directive 5000.1 and Instruction 5000.2. This guidance sets DOD policy for managing all acquisition programs. Among other things, it requires the use of architectures to characterize the interrelationships and interactions between U.S., allied, and coalition systems. DOD has initiated efforts to develop an architecture for combat identification, but they have not been comprehensive or adopted by the military services. The first effort began in 1994 with the creation of a Combat Identification Task Force. Among other things, such as identifying promising combat identification technologies for a planned demonstration, the Task Force sought to develop an overall architecture for combat identification through an architecture working group. However, this effort only focused on specific systems and how they would work together. It did not define the operational elements and activities required to support a future warfighting vision or technical standards. Both views are integral to an overall architecture. According to DOD, for example, the operational view is useful for facilitating a number of actions across DOD, such as defining operational requirements to be supported by physical resources and systems. The technical view enables interoperability and compatibility of systems, by providing the standards, criteria, and reference models upon which engineering specifications are based, common building blocks are established, and applications are developed. The work of the architecture working group also excluded elements integral to the battlefield, such as dismounted soldiers, ships, air defense sites, and air-to-ground missions other than close-air support. Additionally, the architecture developed only dealt with the need to identify forces as being either friendly or hostile. It did not address the need to further distinguish targeted systems by class (e.g., “tank” vs. “truck”), platform (e.g., MIG 29 vs. T-72 Main Battle Tank) or intent (e.g., a defecting vs. an attacking platform). More critically, the architecture was never adopted by the services. Subsequent work began in January 2000 when the Joint Chiefs of Staff’s Combat Identification Assessment Division began planning draft guidance on an effort to analyze alternative current and evolving combat identification technologies to support development of an operational architecture. The analysis is expected to take over 2 years to complete at an estimated cost of $10 million. However, this effort is to focus on surface-to-surface and air-to-surface military operations and not to include air-to-air or surface-to-air operations. While the draft guidance for the analysis indicated that the Army should lead the effort with support from the other services, thus far, only the Air Force has budgeted funds— $2 million—toward accomplishing this task. Similarly, in January 2001, the Assessment Division described efforts to develop the operational architecture itself. However, this effort is currently unfunded. According to DOD officials, the reasons for the current lack of funding include the difficulty of reflecting such efforts in DOD’s budgets in a timely manner and addressing competing service funding priorities. Architectures enable organizations to know their portfolio of desired systems and to develop a clear understanding of how these systems will collectively support and carry out their objectives. Moreover, they help ensure that systems are interoperable, function together effectively, and are cost-effective over their life cycles. Our previous reviews at the Federal Aviation Administration, Customs Service, Department of Education, Internal Revenue Service, Bureau of Indian Affairs, and National Oceanic and Atmospheric Administration have shown that while the absence of a complete architecture does not guarantee the failure of system modernization efforts, it does greatly increase the risk that agencies will spend more money and time than necessary to ensure that systems are compatible and in line with business needs. Our previous work reviewing DOD’s combat identification efforts has shown that DOD is confronting such risks. In 1993, we reported on the Army’s ongoing efforts to develop its Battlefield Combat Identification System (see fig. 1)—a system designed to provide a ground-to-ground and potentially an air (helicopter)-to-ground cooperative identification capability. We found that the Army planned to spend up to $100 million on a near-term combat identification system even though the system might eventually be discarded if it could not be integrated into a long-term solution. We also reported that the Army planned to eventually buy 1,520 of the near-term systems to equip some forces even though that number would not be sufficient for a larger-scale operation. Additionally, absent the understanding provided by an enterprise architecture, the services risk being unable to effectively define and develop weapon system requirements (e.g., system characteristics, functions, and performance parameters).