Establish a top-level work breakdown structure (WBS) to estimate the scope of the project.


The WBS evolves with the project. A top-level WBS can serve to structure initial estimating. The development of a WBS divides the overall project into an interconnected set of manageable components.

Typically, the WBS is a product, work product, or task oriented structure that provides a scheme for identifying and organizing the logical units of work to be managed, which are called “work packages.” The WBS provides a reference and organizational mechanism for assigning effort, schedule, and responsibility and is used as the underlying framework to plan, organize, and control the work done on the project.

Some projects use the term “contract WBS” to refer to the portion of the WBS placed under contract (possibly the entire WBS). Not all projects have a contract WBS (e.g., internally funded development).

Example Work Products

  1. Task descriptions
  2. Work package descriptions
  3. WBS


1. Develop a WBS.

The WBS provides a scheme for organizing the project’s work. The WBS should permit the identification of the following items:

  • Risks and their mitigation tasks
  • Tasks for deliverables and supporting activities
  • Tasks for skill and knowledge acquisition
  • Tasks for the development of needed support plans, such as configuration management, quality assurance, and verification plans
  • Tasks for the integration and management of nondevelopmental items

2.Define the work packages in sufficient detail so that estimates of project tasks, responsibilities, and schedule can be specified.

The top-level WBS is intended to help gauge the project work effort for tasks and organizational roles and responsibilities. The amount of detail in the WBS at this level helps in developing realistic schedules, thereby minimizing the need for management reserve.

3. Identify products and product components to be externally acquired.

Refer to the Supplier Agreement Management (SAM) (CMMI-DEV) process area for more information about managing the acquisition of products and services from suppliers.

4. Identify work products to be reused.