How to Create a Work Breakdown Structure (WBS)

According to the Project Management Body of Knowledge (PMBOK), creating a WBS is one of the Scope Management knowledge area processes that takes place during the Planning process group (See for the table that displays the PMBOK processes mapped to knowledge area and process group.

Creating a Work Breakdown Structure (WBS) can seem simple conceptually, but there are factors to consider when applying it practically.  However, before jumping into the steps to create a WBS, it is important to understand the need for a WBS.

What is a Work Breakdown Structure?

A WBS is defined by the PMBOK as “a deliverable-oriented hierarchical decomposition of the work to be executed by the project team to accomplish the project objectives and created the required deliverables”.   A WBS does not depict time or order of execution.  Rather, its a breakdown of all the work to be done for a project.

A WBS can be organized are functionally, or by phase as indicated in the example below:

Phase-Based Work Breakdown Structure
Phase-Based Work Breakdown Structure


Although the above figure is a graphical example, a WBS can be developed in other formats as well.  In fact, on larger projects, Microsoft Excel or Microsoft Project are better tools for large WBS structures that contain hundreds, or thousands, of lines.

A WBS contains 4 levels as indicated on the above figure (for more information on the construct of a WBS, visit the Wikipedia site as well:   All the work contained in the child elements of a WBS component must equal the complete work to be completed for the parent element.  Note that the work package is the lowest level of decomposition. This is the lowest level WBS component and is called a work package.  This level is considered to be a manageable component of work, which can be scheduled, cost estimated, monitored and controlled.  Generally, a work package should not contain less than 80 hours of work.  There is lots more information on the internet about the WBS levels 1 to 4.  We will not focus on this.  The best resource on the details of each WBS level can be found in the PMBOK.

The main goal of this post is to:

  • Explain the significance of a WBS
  • Provide information on how to facilitate a WBS decomposition exercise
  • provide supporting WBS tools and templates

Why is a Work Breakdown Structure Important?

A WBS is one of the most critical components of a successful project because it forces the project team to carefully consider all the pieces of a project.  Specifically on large projects, it is practically impossible for one person to consider all the work necessary to complete the project.  If the project team does not take the time to decompose the work and consider all the work components, then it is safe to assume that the project team has not performed due dilegence to ensure that all the work has been identified.

On many projects, the WBS development exercise is not performed.  Rather, the project jumps into developing a project schedule.  All too often, the project seems to be progressing smoothly only to realize, later, that a key activity or dependency is missing from the project schedule because it was not considered during the schedule development.  And it was not considered during schedule development because the WBS work decomposition was not performed to try to identify all the work necessary to deliver the product or service.  Or the project schedule underestimated the level of effort for an activity, thus causing delays and potential cost overruns.  Again, the WBS exercise could help with time estimation and sequencing of activities since all the people involved in performing the work are colocated for a period of time with the one purpose of identifying all the work and providing estimates and dependencies on the work.

The WBS exercise of decomposing the work as a team is also a team-building effort.  It implicately creates a sense of agreement as well as accountability among the project team members.

Now, let’s jump into the process of developing a WBS.

How to Facilitate a Work Breakdown Structure Decomposition Exercise?

A successfully developed WBS involves the project team, usually sitting in a half-day to multi-day workshop, to decompose all the work necessary to complete the work.

The main purpose of a WBS excercise is to:

  1. Structure and organize the WBS
  2. Decompose each WBS component into lower level components by identifying all the deliverables and activities necessary to complete the WBS component
  3. Complete a WBS Dictionary Card for each WBS component that contains a detailed explanation of the component, level of effort and other information that could help during project schedule development. (As part of this activity, assigning unique WBS ID numbers to each WBS component is also critical to keep the WBS Cards organized)
  4. Verify that the level of decomposition is sufficient at the Work Package level (the lowest level of the WBS decomposition) to ensure that the work is not too large or small, but manageable.

The steps documented in this section are meant to serve as guidance.  Depending on the size of the project and the culture of the organization, there can be variations of this activity.  However, this should provide guidance on how to use the entire project team to develop the WBS.

1. Organize a WBS Workshop

The WBS workshop should include, at a minimum, the key members of the project team.  Keep in mind that the point of the WBS exercise is to consider all the work required to deliver the final product or service.  So you need the people on the team who are actually doing the work to be there and be actively involved.  Stress the importance of this to the project sponsor and to the project team managers (in a matrixed team, the support of the project team managers is critical since they are allocating resources to the project).

2. Decompose the Work

Decompose the workshop to manageable components of work called work packages, hopefully under the guidance and facilitation of the WBS workshop organizer.  The following tips help facilitate the workshop and make the process of collecting the information simpler.

  • Break up the team into smaller groups that are organized by level 2 of the WBS (In our phase-based WBS, level 2 is the Planning, Implementing, Monitoring & Control and Deployment level.  It is much easier to go into the workshop with a high level WBS structure so that the team doesn not waste valuable workshop time trying to determine the high level WBS structure.
  • Use blank WBS Dictionary cards to collect all the decomposed work elements
    • [downlaod a sample WBS Dictionary Card here.  This sheet has 2 cards, so cut the sheets in half.]
  • Ensure that the teams assign WBS numbers to all the WBS Dictionary Cards they complete.
  • Ensure that there are enough WBS support staff to walk around the room and ensure that the teams understand how to decompose the work using the WBS Dictionary Cards.  Specifically, if the WBS Dictionary Cards are not assigned WBS Numbers, then the cards will be difficult to sort correctly when they are collected later.
  • A good idea it to provide a table workspace for each team so that they can organize their dictionary cards on a table.

3. Compile the WBS Information

Compile the collected WBS Dictionary Cards to create a WBS and supporting WBS Dictionary Document.  The WBS Dictionary Document is essentially an organized collection of the WBS Dictionary Cards.

What Tools Do I Need to Create a Work Breakdown Structure?

There are lots of tools out there to assist with WBS Development.  But the work mentioned here can be performed with Microsoft Office and Excel.   A WBS Dictionary Document Template is available for download below.  Additionally available for download is a WBS spreadsheet that can be used to compile the WBS Dictionary Card information.

[download the WBS Dictionary Excel spreadsheet with auto numbering capability for the WBS – Auto-Numbering and in Excel format (Note: Use indentation to control the numbering of the WBS items)]


[download the WBS Dictionary Document Template here]

As you can see from the reference below, entire books have been written about how to develop a WBS and how to facilitate the team activities.  This post is intended as a primer, but expect more posts on the WBS.