Work Breakdown Structure (WBS)
Posted on Wednesday, August 19, 2009
This was posted in Software Engineering
Question. Explain Work Breakdown Structure (WBS).
Answer. Work Breakdown Structure is the scheduling technique. A complex project is made manageable by first breaking it down into individual components in a hierarchical structure, known as the work breakdown structure, or the WBS. Such a structure defines tasks that can be completed independently of other tasks, facilitating resource allocation, assignment of responsibilities, and measurement and control of the project.
The work breakdown structure can be illustrated in a block diagram:
Pitfalls and misconceptions:
- A Work Breakdown Structure is not an exhaustive list of work. It is instead a comprehensive classification of project scope.
- A WBS is not a project plan or a project schedule and it is not a chronological listing. It is considered poor practice to construct a project schedule (e.g. using project management software) before designing a proper WBS. This would be similar to scheduling the activities of home construction before completing the house design. Without concentrating on planned outcomes, it is very difficult to follow the 100% Rule at all levels of the WBS hierarchy.
- A WBS is not an organizational hierarchy. Some practitioners make the mistake of creating a WBS that shadows the organizational chart. While it is common for responsibility to be assigned to organizational elements, a WBS that shadows the organizational structure is not descriptive of the project scope and is not outcome-oriented. See also: responsibility assignment matrix (also called a Staffing Matrix).
- WBS updates, other than progressive elaboration of details, require formal change control. This is another reason why a WBS should be outcome-oriented and not be prescriptive of methods. Methods can, and do, change frequently, but changes in planned outcomes require a higher degree of formality. If outcomes and actions are blended, change control may be too rigid for actions and too informal for outcomes.
- A WBS is not a logic model. Nor is it a strategy map.
