How to Create a Work Breakdown Structure
With the documented scope statement defining the deliverables a project will produce, it's time to begin defining the work that will need to be performed to create those deliverables. The most valuable and effective tool used in this process is the Work Breakdown Structure (WBS).
The WBS is a logical grouping of the deliverables, broken into manageable components. When complete, the WBS contains all of the work required to fulfill the scope of the project, and nothing more. The WBS:
- Captures all deliverables to be produced
- Captures all work to be completed
- Captures internal, external, and interim deliverables
- Includes project management work
There are no set criteria governing how the WBS must be produced, how much detail it contains, the number of components or branches required, or how many levels each branch should contain. There are, however, some stated best practices.
- Begin by identifying how project work is to be reported to stakeholders.
- Identify the major deliverables to be produced by reviewing the scope statement.
- Break each deliverable down into sub-deliverables or interim deliverables.
- Continue decomposing each deliverable to a level where it can be adequately:
- Assigned to a work group
- Assign a unique code to each element to identify it for further tracking.
A WBS can be constructed in a number of ways, including, but not limited to:
- Dividing the project by major Product Deliverables
- Dividing the project by the life cycle phases and then by the deliverables produced in each phase
- Dividing the project by the different resource groups producing the work
- Dividing the project by geographic location of the resources performing the work
- A combination of these methods
As an example, we can construct the WBS for a project undertaken to build a house. The WBS can be constructed based upon the major components of the house as such.
We could also choose to construct the WBS for the same project based upon the phases of the project life cycle being followed.
In each of the above examples, only a partial WBS is being displayed. Regardless of the construction method, more detail would be required. Thus far, only some of the deliverables are identified.
When creating the WBS, the convention is to name deliverables using only a noun, and activities using a verb and a noun. In the first example, we have listed only deliverables, which are stated in a noun form: Blueprints, Project Management, Bath, etc.
In the second example however, note the work listed in the Close branch. The two elements here represent activities since they are stated in a verb-noun format:
- Transfer (verb) Title (noun)
- Close (verb) Financials (noun)
When developing the WBS, it is beneficial to use a standard naming convention and format for all elements included. This allows for ease of report and delineation between deliverables and activities. It is also beneficial to use a consistent method of breaking down the components. For example, to be more consistent with the rest of the WBS, it would be better to display the deliverables to be produced in the Close Phase of the House project, rather than the activities to create them. These deliverables then can be further decomposed to show the activities required to produce them.
Why do we start with the deliverables? There are several reasons:
- Facilitates Summarized Tracking by Project Deliverables instead of activity.
- Facilitates Reporting by Project Deliverables instead of activity.
- Allows the Project Plan to show explicit progress that means something to the customer.
- Gives us metrics to baseline against for future estimates.
Since deliverables are broken down into smaller increments and then to the activities required to complete them, we can readily track and report the status of each deliverable. Being able to tell our customer that we are 90% complete with the frame and 45% complete with the kitchen is more meaningful than telling them that individual activities have been completed.
Developing the WBS can be an excellent team building exercise. Involving different stakeholders in the process provides them the opportunity to:
- Voice their opinions
- Feel confident that all elements are being captured
- Better understand all of the aspects of the project
This often generates a greater commitment to the project and the project team. Engaging stakeholders results in a better defined and organized WBS than the project manager would likely produce on his or her own.
Several techniques can be used in defining the WBS, including:
- Requirements review sessions
- Brainstorming sessions
- Delphi Technique (using anonymous experts)
- Stakeholder interviews
There are two primary approaches used in constructing the WBS:
- Top-Down Approach
- Identifies the highest level components first
- Decomposes the first components into smaller components
- Used when the team has a lot of knowledge about the project
- Bottom-Up Approach
- Identifies all of the activities required through brainstorming or similar activity
- Organizes the activities into logical groupings
- Associates the activities with appropriate deliverables
- Used when the team is less familiar with the type of work being developed