4.3.2.1. Work Breakdown Structure
4.3.2.1. Work Breakdown Structure
The Work Breakdown Structure (WBS) provides a consistent and visible framework for materiel items and contracts within a program throughout its life cycle. It provides a product-oriented division of tasks by breaking down work scope for authorization, tracking, and reporting purposes. The WBS is defined, developed, and maintained throughout the acquisition life cycle based on a disciplined application of the systems engineering (SE) process. The goal is to develop a WBS that defines the logical relationship among all program elements to a specified level. The WBS integrates technical, cost, and schedule parameters, giving the Program Manager a tool to:
- Ensure traceability of all program activities
- Identify significant risk drivers
- Forecast cost and schedule performance
- Develop corrective action plans as needed
There are two types of WBS: (1) the Program WBS and (2) the Contract WBS (including flow-down reporting requirements). The Program WBS provides a framework for specifying program objectives. Each WBS element provides logical summary levels for assessing technical accomplishments, for supporting the required event-based technical reviews, and for measuring cost and schedule performance. It represents the entire program from the Government Program Manager’s responsibility. The contract WBS is the Government-approved WBS for program reporting purposes and includes all program elements (for example, hardware, software, services, data, or facilities), which are the contractor’s responsibility. It includes the contractor’s discretionary extension to lower levels, in accordance with Government direction and the contract Statement of Work (SOW). The WBS depicts the system as a product-oriented tree, which may be found in a system model. Requirements for developing a WBS are found in MIL-STD-881C. The Program Manager, in conjunction with the Systems Engineer, should develop a comprehensive WBS early in the program to support planning, cost and schedule estimates, and risk mitigation activities.
The WBS provides a common thread for the Earned Value Management System (EVMS), the Integrated Master Plan (IMP) and the Integrated Master Schedule (IMS), allowing consistency in understanding and communicating program cost and schedule performance. Additional information about EVMS can be found in DAG Chapter 11 Program Management Activities.
Planning tasks by WBS elements serves as the basis for mapping the development of the technical baseline for estimating and scheduling resource requirements (people, facilities, and equipment). By breaking the system into successively smaller pieces, the Program Manager can ensure all system elements and enabling system elements are identified in terms of cost, schedule, and performance goals in order to reduce risk.
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