This article will provide all the information you need about Work Breakdown Structure (WBS), in preparation for your PMP(r). This information is a consolidation of the PMBOK (r) guide.
What is Work Breakdown Structure?
Work Breakdown Structure (WBS), is the hierarchical breakdown of the total scope for work on a project.
The deliverable to be completed is the top node in the WBS. The project manager must decide how to divide the project work. For inspiration, the project manager might look at past projects from the lessons learned database.
The WBS must be MECE (Mutually Exclusive Collectively Exhaustive). The WBS must contain all the work required to complete the deliverable. No task can be repeated.
The WBS divides the deliverable into its logical parts. The work packages are the lowest level of the WBS. PMI recommends that work packages should be between 8 and 80 hours in length.
The WBS is created by the project manager and assigned to the appropriate team member. The work package must be completed on time by the team member.
What is the difference between an activity and a work package?
The team member responsible for delivering each work package breaks down the individual work packages into activities. The WBS will be assigned to the team member who will decide how the work is broken down and completed. He/she will complete all activities necessary to complete the work package in the given time.
Why is a WBS in PMP (r) important?
Here are 6 reasons why it is important to create a WBS prior to project execution:
It is said that a picture is worth a thousand phrases. This may make it easier for the team understand the deliverables of the project.
The WBS can inform the project manager about what has been completed and what remains to be done.
Cost control is essential for the WBS. Different WBS branches may be associated with different cost control accounts. Executives may want to see the total cost of the project broken down into control accounts when the project manager reports on its status.
Team members can easily be assigned the work packages from the WBS. Each member of the project team can be held accountable for completing the work packages.
The WBS can help speed up project planning. You can use historic WBS as a template.
The PMI recommends that a WBS be created to reduce project risk.
How do I create WBS?
You can create a WBS for a project in two ways: outline or pictorial.
Pictorial Method

The pictorial method makes the WBS look like an organizational chart. However, instead of names, there are tasks. The sum of all the descending nodes adds up to the tasks in each ascending node. This can be helpful when presenting to executives as it will allow them “see” the project.
It can also be used to assign responsibility to team members. Each person can see which part of the project is theirs and how it fits into the larger picture.
The pictorial WBS method is also recommended by PMI for creating a WBS. Here’s an example pictorial WBS

2. Outline Method
The outline method is another way to create a WBS. The outline method is a list of bullet points that has a hierarchy. The sum of all sub-items is equal to the item above.
If you don’t have much time and only need to draw a rough sketch of your WBS, the outline method is a good option.
Here’s an example of a WBS that was created using the outline method.

What is the connection between WBS & RTM?
RTM, the Requirements Traceability Matrix (RTM), ensures that all requirements are met in the deliverable. Each requirement is linked with a component of the WBS. This allows you to ensure that all requirements are met in your project deliverables.
Here’s an example of a RTM.