In the article, we will cover everything you need to know about Work Breakdown Structure (WBS) for your PMP exam. This information is a consolidation from the PMBOK guide.
Work Breakdown Structure (WBS) is the hierarchical decomposition of the total scope of work on the project.
The top node of the WBS is the deliverable to be accomplished. The project manager must decide upon the best method to divide the project work. The project manager may look at historic projects in the lessons learned database for inspiration.
The WBS must be MECE, or Mutually Exclusive Collectively Exhaustive. In other words, the WBS must include all the work required to complete the deliverable and no task can appear twice.
The WBS breaks the deliverable into its logical components. The lowest level of the WBS is the work packages. PMI recommends work packages to be around 8-80 hours long.
The project manager creates the WBS and assigns the work packages to the appropriate team member. The team member is responsible for completing the work package on time.
The individual work packages are decomposed into activities by the team member responsible for delivering the work package. After the WBS is assigned, the team member will decide how the work in the work package is divided and completed. S/he will do all the activities required to complete the work package on time.
Here are the top 6 reasons why it is essential to create a WBS before project execution begins:
There are two ways to create a WBS for your project: pictorial or outline.
The the pictorial method, the WBS looks like an organizational chart, except instead of names in the chart there are tasks. The sum of the descending nodes add up to all the tasks in the ascending node.
Having a picture representation of all the tasks can be useful when presenting to executives because it will allow them to “see” what is going on in the project.
It can also be useful when assigning responsibility to team members. Each person can visually see what part of the project they are responsible for and how their part fits in the big picture.
The pictorial WBS is also PMI’s recommended method of creating a WBS. Here is an example of a pictorial WBS:
Another method to create a WBS is through the outline method. The outline method looks like a list of bullet points with hierarchy. The sum of the sub-items add up to the item above it.
The outline method is useful when you do not have a lot of time, and need to make a rough sketch of the WBS.
Here is an example of a WBS created with the outline method:
RTM is the Requirements Traceability Matrix, and it ensures that all the requirements are met in the deliverable. Each requirement is linked to a component on the WBS. In this way, you can ensure that all of the requirements will be met in your project deliverables.
Here is an example of a RTM:
The WBS and WBS dictionary work together to define the project scope. Because the WBS is a hierarchy chart, you can’t fit a lot of information into the individual cells. However, you may have additional information about that task that you want your project team to know about. Thus, you will include the extra information in the WBS dictionary, which tells you more about each of the tasks on the WBS.