The Project Management Book of Knowledge (PMBOK) explains the Work Breakdown Structure as a deliverable-oriented hierarchical analysis of the work to be executed by the project team. There are two types of Work Breakdown Structures:
Work Breakdown Structures
- Deliverable-Based
- Phase-Based.
The most common – as well as preferred – approach is the Deliverable-Based approach
The Work Breakdown Structure (WBS) is responsible for breaking down the work – that is to be performed in a particular project – into smaller elements. This action provides a greater probability that every major and minor activity will be accounted for. The WBS is formulated according to the way that the work in the project will be performed. In addition, the Work Breakdown Structure reflects the way in which project costs and data will be summarised and eventually reported on.
The WBS helps to accomplish the following key objectives:
- Develops an objective and rational view of the amount of work that is needed.
- Assists the team grasps the skills and amount of resources needed for the project.
- Provides a clear framework for assigning to individuals a clear task definition and delegates the responsibility for completion.
- Lays a foundation for analysing the task dependencies and for isolating as well as managing risks.
- Provides a foundation for developing a bottom-up assessment for the project schedule.
- Allows trade-offs to be made consciously as well as with the proper consensus involved.
The Work Breakdown Structure is the first step in the process developing a detailed work plan for the project. Task identification and WBS create a bridge from the early scope definition to the creation of a detailed project schedule.



