Defense Primer: U.S. Army Force Structure Development Process

Introduction

The U.S. Army has changed the units and organizations comprising its force structure throughout its history, which dates to 1775. Force structure can be described as the number and types (infantry, artillery, engineer, etc.) of Army units containing soldiers, weapons, and equipment. Changes to Army force structure have occurred for various reasons, including

• evolution of national security requirements;
• introduction of new technologies and weapons;
• adoption of new tactics and techniques;
• assignment of new missions; and
• consideration of budgetary factors.

Under Article I, Section 8, of the Constitution, Congress has the authority to "raise and support Armies" and "make Rules for the Government and Regulation of the land and naval Forces," among other powers pertaining to the armed forces. Congress typically considers annual legislation to authorize the size of the armed forces, including Army components, and to appropriate funding for defense. Under Title 10, Section 113, of the U.S. Code, Congress has generally delegated the daily administrative management of the U.S. military (including determination of force structure) to the Secretary of Defense, who is using "Secretary of War" as a "secondary title" under Executive Order (EO) 14347 dated September 5, 2025. Under Title 10, Section 7013, of the U.S. Code, the Secretary of the Army is responsible for the administration, training, equipping, and organization of the Army.

Background

The process of developing and fielding Army units is known as Force Management (FM), an administrative function translating strategic security requirements into resourced, trained, and ready forces. The FM process informs annual Army budget requests to Congress and guides budget implementation once Congress authorizes and appropriates funding and sets end strength.

The Army uses an iterative, five-phase Force Development (FD) process (Figure 1) to design and authorize its units. This process is usually guided by the National Security Strategy (NSS), the National Defense Strategy (NDS), Army Strategy, and Army senior leader guidance.

Overview of Force Development

FD is the Army's internal process that defines military capabilities, designs force structure for the Active and Reserve Components (Army Reserve and Army National Guard), and produces plans to translate organizational capabilities and concepts into a trained and ready Total Army (Active and Reserve components). Information on the Army FD process used in this report is taken from How the Army Runs: A Senior Leader Reference Handbook, 2023-2027, 2025.

Figure 1. Army Force Development Process

Source: CRS graphic based on a diagram in U.S. Army War College, How the Army Runs: A Senior Leader Reference Handbook, 2023-2027, 2025, p. 4-5. Notes: FDU = Force Design Update. TOE = Table of Organization and Equipment. TAA = Total Army Analysis. SACS = Structure and Composition. PER = Personnel. LOG = Logistics. According the Warfighting Acquisition University and the Defense Acquisition University, DOTMLPF-P is an acronym representing aspects of Doctrine, Organization, Training, Materiel, Leadership and Education, Personnel, Facilities, and Policy. It is an analytical framework used to "think through managing change—specifically, identifying the second- and third-order effects on all of these aspects precipitated by a desire (or need) to make a change in any one or more of these aspects." BOIP (Basis of Issue Plan) is an official document prescribing "the specific type and quantity of equipment, support items, and associated personnel needed to operate and maintain new or improved materiel systems in a unit."

Army Force Development Process

Phase I: Determine Capability Requirements

• The FD process begins with determining the Army's desired operational capabilities as specified in the aforementioned strategic documents and Combatant Commander (CCDR) requirements. This strategic guidance is informed by current and projected geopolitical landscapes, usually articulated in a joint operating environment (JOE) concept document. A 2024 Army assessment, The Operational Environment 2024-2034, states that its forces may have to adapt to a future operational environment characterized in part by a proliferation of uncrewed systems, hyperconnected communications, and challenged logistics.
• The Department of Defense (DOD), which is "using a secondary Department of War designation" under EO 14347, and the Army integrate the Joint Force Requirements Process (JFRP)—which replaced the Joint Capabilities Integration and Development System (JCIDS) in 2025—the Defense Acquisition System (DAS), and the Planning, Programming, Budgeting, and Execution (PPBE) processes to develop, fund, and acquire warfighting capabilities that the Army deems operationally effective and affordable.
• How urgently a new capability is viewed as required dictates what FD approach the services use. Deliberate planning is used when time permits and follows a traditional track using a full Capabilities-Based Assessment (CBA) captured in an Initial Capabilities Document (ICD).
• When a threat is identified by CCDRs that requires rapid action, the capability requirement may qualify for submission as a Joint Emergent Operational Needs (JEON), which allows for expedited validation and rapid acquisition. If operational needs are identified in ongoing operations that represent potential mission failure or unacceptable loss of life, a Joint Urgent Operational Needs (JUON) may be submitted. In both cases, these needs can be met by a materiel (i.e., weapon or system) or force structure solution or a combination of both.

Phase II: Design Organizations

• A DOTMLPF-P (i.e., Doctrine, Organization, Training, Materiel, Leadership and Education, Personnel, Facilities, and Policy) analysis determines whether a new or modified organization is needed to meet required capabilities. Warfighting and training requirements are also factored in such analysis.
• The Army then conducts a Force Design Update (FDU), which designs organizational structure solutions to address capability shortfalls that cannot be corrected through other means, such as doctrine, training, and leadership. FDUs are submitted to the Army Deputy Chief of Staff for Operations, Plans, and Training (G-3/5/7) staff directorates semiannually for approval and are evaluated across multiple criteria for feasibility and suitability.

Phase III: Develop Organizational Models

• In conjunction with the FDU process, developers of the new organizational structure create a Table of Organization and Equipment (TOE) describing the operational mission and capabilities of the unit and detailing the unit's personnel and equipment requirements. The TOE provides the basis for developing authorization documents and determining resource requirements.

Phase IV: Determine Organizational Authorizations

• In this phase, Army leadership makes force structure decisions based on joint force and Army objectives in an environment of congressionally and DOD-imposed constraints and resource limitations. The purpose is to develop the evolving Army force structure across the Total Army over the Program Objective Memorandum (POM) time period.
• Total Army Analysis (TAA) is a process intended to keep the Army within congressional end strength guidance while fulfilling DOD objectives. The Operational Force (OF) TAA shapes the force structure required to meet mission needs. The Generating Force (GF) TAA determines the right size and composition of the Institutional Army (i.e., infrastructure, organizations, and generating force that support, sustain, and prepare operational fighting forces) to support the Army's future structure requirements. TAA is conducted annually to ensure the appropriate force structure across the Future Years Defense Program (FYDP) and to form the analytical underpinning used to justify the POM Force (i.e., the force recommended and supported by resource requests).
• TAA Phase I is a quantitative analysis in the form of scenarios, wargaming, historical analysis, directed guidance, sustainment requirements, and deployment models. This analysis validates the capability demands.
• TAA Phase II is a resource determination phase utilizing current forces available and identifying any required emerging growth to the force. This phase has the potential to be contentious as officials work to compromise to meet mission objectives within end strength constraints. This phase produces the POM Force, which is submitted to the Secretary of the Army for approval.
• TAA Phase III results in the Force Synchronization Review (FSR), which implements the decisions and provides continual assessment. The FSR allows Army staff to identify problems and develop alternatives if the previous guidance becomes infeasible because of changing resourcing factors.
• The products of the TAA are the Army POM Force and the Army Structure (ARSTRUC) Memorandum. The publication of the ARSTRUC Memorandum directs commands to make appropriate adjustments to their force structure and completes the TAA process.

Phase V: Document Organizational Authorizations

• The final phase of the FD process captures decisions by integrating the organizational models with the actual authorizations determined by resource limitations. Each unit in the Army has an authorization document that identifies their mission, function, and structure. The unit uses these documents to requisition personnel and equipment and as a basis to evaluate their readiness. These documents are generally modified TOE (MTOE) or Tables of Distribution and Allowances (TDA) depending on the type of unit documented.

Related CRS Products

CRS In Focus IF10831, Defense Primer: Future Years Defense Program (FYDP), by Cameron M. Keys and Alexandra G. Neenan

CRS In Focus IF12817, Defense Primer: Joint Capabilities Integration and Development System (JCIDS), by Alexandra G. Neenan