Work Breakdown Structure (WBS)
By Donna Ritter
A work breakdown structure (WBS) maps out the deliverables of the project, with sub deliverables and activities stemming in a tree format. A Guide to the PMBOK describes a WBS this way: “A WBS is a deliverable oriented grouping of project components that organizes and defines the total scope of the project; work not defined in the WBS is outside of the project”.
A Work Breakdown Structure is a break down of the work packages to enable you to roll them back up to a schedule that is complete. A work package is usually no more than 40 hours.
The WBS should detail the full scope of work needed to complete the project. Accuracy and completeness are required when composing your WBS.
Decomposition is one of the tools you will use when preparing your WBS. You should be able to break down the deliverables to a point where you can easily plan, execute, control and close out the project deliverables. Each work package should be able to be easily estimated in the Activity Definition Process which can applied in the following 4 major steps:
- Identify all of the major deliverables. The PMBOK is clear on noting that the deliverables should be defined according to the way the project is organized. One way is to organize a project in phases. The phases become the first level of decomposition, followed by the deliverables.
- Estimate cost and duration. If that cannot be done, then you have to decompose further until the work package can be estimated. I usually use a work package of 20-40 hours at the most. Not all deliverables will have the same level of decomposition. In any case, a schedule cannot be made until the WBS is complete and has estimates that are as accurate as possible.
- Identify components that make up the deliverables.
- Verify that each component listed is clear, complete and necessary to fulfill the requirements of the deliverable. Also, you need to easily add up all the estimates, budget and assignments to create a solid schedule.
A WBS looks very much like a flow chart. The goal is to break down the work so that each work package can be assigned to a specific person for accountability and the Project Manager can easily manage the schedule knowing that all parts of the project have been broken down to their smallest part.
Each Work package is assigned a unique identifier and these are documented in the WBS dictionary. The dictionary includes a description of the work package, costs, budgets, schedule dates, resource assignments and activity descriptions.
This process sounds like a lot of work, but it is a known fact that the more you plan, the better you will be in the end.
The WBS plays a major part of Project Management. For those taking the PMP certification course, I was told that if you didn’t know the answer to a question WBS probably was it!
Donna Ritter is a passionate Senior Level Software PMP Certified Project Manager with a proven track record designing and developing complex distributed systems solutions at three major technology companies and several small ones. Donna has designed business management processes required for clients depending on company size and culture during her yeas of international experience. She has also delivered Enterprise systems management solutions to Fortune 500 companies designed for multi-cultural environments. Donna is a results-driven leader with extensive experience in practical application of best industry practices with teams who must deliver quality products despite significant time, resource, and technical challenges. She have proven abilities to form and manage cross-organizational teams and programs achieving breakthrough results. Donna maintains a professional blog: Project Management and Life Coaching.