Project Management: Work Breakdown Structure

Successful project management relies on thorough planning.  The more detailed and focused your project plannning is, the more accurate your estimates are and the more manageable your project.  The work breakdown structure (WBS) is a project management deliverable that decomposes the project into smaller components.  It provides the foundation for defining work as it relates to project objectives.  It groups a project's work elements in a way that helps organize and define the total work scope of the project. 


The WBS is used in project as follows:

• To define the project’s scope of work in terms of deliverables and to further decompose those deliverables into specific work components (which facilitates tasks such as estimating, scheduling and resource allocation)
• To provide the project management team with a framework on which to base project status and progress reports
• To facilitate communication between the project manager and stakeholders, as it can be used a communication tool regarding project scope  
• To be used as a critical input to other project management processes such as: schedule network diagrams, activity definitions, project schedules, performance reports

The work breakdown is structured in the form of a tree, which shows a subdivision of effort required to achieve an objective.  The WBS is developed by starting with the end objective and successively subdividing it into manageable components in terms of size, duration, and responsibility, which include all steps necessary to achieve the objective.  Below is an example of WBS for building a car.  As you can see, the ultimate goal -- the car -- sits atop the WBS, while the individual components that go into making the car, sit underneath. 

A WBS permits the aggregation of subordinate costs for tasks, materials, etc., into their successively higher level “parent” tasks, materials, etc. For each element of the work breakdown structure, a description of the task to be performed is generated.


The WBS is organized around the primary products of the project (or planned outcomes).  Since the planned outcomes are the desired ends of the project (i.e. the car), they form a relatively stable set of categories in which the costs of the planned tasks needed to achieve them can be collected.