The work breakdown structure (WBS) consists of the defined set of tasks that must be accomplished and milestones that must be met on a project. Each task represents the creation or modification of a part of the product and may include items such as

• Hardware and/or software products to be produced

• Services and support tasks that must be accomplished

• Procurement of equipment, tools, and facilities

• Training of project personnel

The WBS defines the basis for planning the project, allocating work, and tasking resources in a coordinated and focused manner. The WBS serves as the mechanism for program scheduling and fiscal planning and provides the means to coordinate and control the diverse activities of a program, and to report on progress and status during the project.

The WBS subdivides projects into manageable units of work to be performed through the definition of various levels of hierarchy described and illustrated. The top of the hierarchy is the scope of the project. Each succeeding level in the hierarchy provides greater detail of the groupings and individual tasks to be performed. An example of a typical breakdown of levels in the hierarchical structure for a WBS is provided.

There are typically three different forms of the WBS that can be applied to define and allocate work in a software project: An end-item or product WBS structure. A functional WBS and an organizational WBS structure. Creating and using WBS are detailed in other article.