In project management, the work breakdown structure (WBS) is a hierarchical breakdown of a project’s deliverables or phases. With the WBS, project managers can organize project activities into different categories of work. Each layer of the WBS represents a detailed definition of a stage of the project. It breaks the project down into different phases of work. All together, the Work Breakdown Structure represents all work performed in the project.

When created prior to adding activities, the WBS can also act as an outline. By first breaking the project down into phases of work, it’s easier to visualize the project as a whole. Project managers will use the WBS as a guide to break these phases down into individual activities and tasks – creating the project as a whole.

For most organizations, the work breakdown structure is created during the planning phase of the project. Although not a project management requirement, most contracts will require the creation of a well defined WBS. Even if it’s not a requirement, however, the WBS will make it much easier to navigate through the project. Luckily, most project management programs, like Primavera P6, Primavera Cloud, and Microsoft Project, make it easy to create a WBS.

Why is the WBS important for project management?

Even if you are not required to create a WBS, it can be extremely useful for managing your project. Some benefits to creating a work breakdown structure include:

Breaks down complex projects

When working with a large, complex project with thousands of tasks, project management can seem overwhelming. Work breakdown structures allow you to break projects down into smaller, more manageable phases. In scheduling programs like P6 or OPC, you can view WBS layers as colored grouping bands. Rather than viewing a list of thousands of activities, you can organize activities by their associated phase using the WBS.

Provides clarity for project teams

Most projects involve many people and teams working together to meet deliverables. With a work breakdown structure, you can clearly display responsibilities by project phase. This ensures that every team member knows what work they need to do to keep the project running.

Helps avoid project management issues

With a large project, it is common to run into issues like missed deadlines, increased scope, or an overrun budget. Using a WBS, you can track these values for groups of activities – rather than each individual task. Tracking these deliverables at the WBS level can help you make sure that your project stays on track.

Assists with measuring project performance

You can measure project performance by analyzing whether activities have finished on time or within budget. Without a WBS, you would need to analyze each activity’s dates and costs individually. However, with the WBS, you can view this data summarized to the specific WBS layer. This will help you quickly see your project’s current status.

WBS Components

Before we dive too much deeper into what the WBS is, we should first go over some definitions. These are all key components that make up a work breakdown structure.

WBS Levels

A work breakdown structure breaks down a project’s work into hierarchical levels, or layers. WBS levels make up the overall work breakdown structure. The WBS can have as many levels as needed, but most structures have at least 3 levels. These levels typically represent specific phases of the project – such as Preconstruction and Construction. You can break down main levels into sub-levels, or child levels to build a hierarchy. For example, a Preconstruction level might have sub-levels of Mobilization, Submittals, and Procurement.

Scope

The project scope is all of the work that you must do in order to complete the project. You will not only need to know what this work is, but also details about it – such as time and budget constraints. Ultimately, you’ll be breaking this scope down into WBS levels – and further breaking it down into individual activities.

Deliverables

Project deliverables are the end result of work performed in a project. This is the product, service, or goal that you can achieve through work performance. Projects often have deliverables for different stages. A deliverable-based WBS focuses on each of the project’s deliverables to create the project plan.

Phases

Project phases are the phases that you need to complete in order to complete your project. For example, a construction project generally has 3 main phases: Preconstruction, Construction, and Project Completion. Of course, you can break these phases down into sub-phases to better describe the sequence of work. A process-based WBS focuses on the specific project phases required to complete your project.

Activities (Tasks)

Activities, also known as tasks, are actions required to complete the project. These represent the individual pieces of work performed to complete the project’s scope. While the WBS breaks the project down into distinct phases, the activities break those WBS layers down further. For each task, you’ll generally enter in a duration, calendar, and dependencies with other activities. Creating a WBS before defining tasks is useful because it provides an overall roadmap to project completion.

Types of Work Breakdown Structures

You can create work breakdown structures in several different ways. In project management, there are typically two types of WBS: process-based and deliverable-based. Project managers can choose to use either one or the other, or both together, to define the project’s scope.

Process-Based Work Breakdown Structure  

A process-based WBS divides the project into different phases. This WBS has the project or deliverables at the top, with layers breaking the project into phases of work. These phases can include Pre-Construction, Construction, and Project Completion. You can break these major phases down into sub-phases to create a hierarchical outline of the project’s work

Deliverable-Based Work Breakdown Structure

A deliverable-based WBS will break the project down into different areas of project scope – like deliverables and work packages. This type of WBS defines the project by the individual deliverables needed to complete the project. A deliverable-based WBS can be useful to help guide the project’s scope by the necessary deliverables.

It is ultimately up to the organization to determine which WBS type to use. Different projects may require different types of work breakdowns. It is also possible to create a WBS that combines both process and deliverables. This can track both the project’s phases of work and the specific deliverables needed.

Work Breakdown Structure Displays

You’ll see work breakdown structures displayed in various ways. Typically, the WBS display depends on the project management software that you are using. However, most programs allow you to switch between different WBS displays as needed.

WBS List

A work breakdown structure list is an outline of each WBS layer. The hierarchy of the structure will typically display in ID numbers, or codes. In most scheduling applications, like Primavera P6, Primavera Cloud, and Microsoft Project, this is the default WBS display.

WBS Gantt Chart

In project management, the Gantt Chart allows you to visualize each of the project’s tasks on a timeline. This can assist you in finding important project details – like milestone dates. The Gantt Chart will show when each activity starts and finishes, their durations, and their dependencies to one another. A WBS Gantt chart provides the same for each WBS layer. This allows you to view WBS layers on a dynamic timeline. In Primavera P6, Primavera Cloud, and Microsoft Project, a WBS Gantt Chart will display along with the WBS list. 

WBS Tree Diagram

A work breakdown structure tree diagram, also called a WBS chart, displays each WBS layer through a connected network diagram. The project itself is at the top of the diagram. Each sub layer below it displays the WBS hierarchy. In both Primavera P6 and Microsoft Project, you can display the WBS as a tree diagram. However, this typically will not display by default. Instead, you’ll need to adjust your view or layout to see this display.

WBS Examples

Now that we’ve gone over the basics of what a work breakdown structure is, let’s take a look at an example of one. The following project involves the construction of an addition to a commercial office building. Because this project features a variety of phases and tasks, the WBS will help break down the project into more manageable chunks of work.

The top layer of the WBS is the overall deliverable – or the project as a whole. For this project, the overall deliverable would be the construction of the office building addition. There are 6 phases to this project. Each WBS layer represents a main phase of work: Design & Engineering, Foundation, Structure, Mechanicals, Exterior Finishes, and Interior Finishes. We can break these phases down into sub-phases to better describe the work performed. For example, we’ve broken Exterior Finishes down into sub layers of Brick, Roof, and Doors & Windows. This gives us a WBS with 3 hierarchical levels.

With your WBS phases thought out, you can begin to construct it by creating WBS levels. The top level of the WBS should be the final project deliverable – or the project itself. You should add additional sub-levels to define the structure. You can create these levels differently depending on the type of WBS you’re aiming to create. For deliverable-based WBS, you can base your levels off of the project’s deliverables. On the other hand, for a process-based WBS, you’ll create levels based off of the project’s phases. You can add as many WBS levels as needed to describe the project. With a work breakdown structure, you now have a guide to better understand the steps involved to complete the project.

How to Create a Work Breakdown Structure

Now that we understand the WBS structure, let’s go over how to create it. Most scheduling programs make this process very easy – so following all these steps may not be necessary. 

On a basic level, there are 7 steps required to create a successful work breakdown structure:

1. Define the Project Scope

The first step in creating a work breakdown structure is to have a clearly defined project scope. You will want to know what the end goal is for the project and what you need to do to get there. It may be useful to define further project details here as well. This can include the start and finish dates, duration, budget, and project team. 

2. Identify Project Deliverables

Next you will want to identify and list all the project deliverables. Deliverables are the end-products of the work performed during the project. A single project will have several deliverables. For example, construction projects often require deliverables, such as submittals, proposals, and reports. If you plan on creating a deliverable-based WBS, you will want to fully define this list. However, even for a process-based WBS, it’s useful to have the deliverables identified beforehand.

3. Identify Project Phases

Along with deliverables, you will also want to identify the phases of the project. You will want to think about what type of work is required for project completion. For example, a construction project will generally have phases of Procurement, Earthwork, and Structure. Often, you’ll break these phases down into sub-phases. With Earthwork, you might break down the phase into subphases of Grading and Utilities. If you plan on creating a process-based WBS, this step will be necessary to create the WBS levels.

4. Create WBS levels

Finally, you can begin to construct your WBS by creating WBS levels. The top level of the WBS should be the final project deliverable. You should add additional sub-levels to define the structure. You can create these levels differently depending on the type of WBS you’re aiming to create. For a deliverable-based WBS, you can base your levels off of the project’s deliverables. A process-based WBS, on the other hand, should have layers based off of the project’s phases. You can add as many WBS levels as needed to reach the project’s completion.

5. Assign tasks to WBS levels

With the work breakdown structure created, you can now use it to help create activities. You can do this by taking the defined deliverable and breaking it down into every activity necessary to complete it. After you have created these tasks you can add them to the different WBS levels. This will give you a project plan. The project plan will show you all of the work that you will need to do and the order in which they should be done.

6. Assign Responsibility

When working with a project team, you may want to assign different WBS levels and/or tasks to different team members. This will allow each team member to know exactly what their role is within the project. With a clear understanding of their role, team members can work to ensure that they complete each required task in time and within budget. 

7. Create a visual display*

Finally, you will want to create a visual presentation of the WBS to refer back to as needed. This could either be a simple hierarchical list, a tree diagram, or a Gantt Chart display, as covered earlier. A Gantt Chart display can be especially useful, as it will show when each WBS layer is set to begin and end and how long they will take to complete

*Most project management applications, like Primavera P6, Primavera Cloud, and Microsoft Project, will automatically create a WBS display for you once you define the layers. These programs will automatically create all three types of WBS displays: a hierarchical list, a tree diagram chart, and a Gantt chart.

WBS Software

Although it is possible to create a work breakdown structure by hand,we recommend that you use a scheduling program instead. Without the software, creating a work breakdown structure will be a daunting, time consuming task. When creating a WBS by hand, it is also much more likely you will make critical errors that affect the overall project. Additionally, most project management applications will automatically create visual WBS displays. This lessens the amount of time needed to complete and maintain a WBS. 

There are a variety of different project management programs available to assist with WBS creation. Here at Taradigm, we offer the premier CPM scheduling applications, including Primavera P6, Oracle Primavera Cloud, and Microsoft Project. These programs not only make creating a WBS easier, but they are also powerful scheduling tools.

If you plan on utilizing Primavera P6, Oracle Primavera Cloud, or Microsoft Project for your WBS and project management needs, it may be a good idea to attend a training course.  At Taradigm, we offer training in all of these programs with a live, experienced instructor. We also offer self-paced online video training for Primavera P6.

Lastly, for those who would like to outsource their scheduling, we specialize in WBS creation, CPM training, and scheduling. Please feel free to contact us for more information.

If you have any comments, questions or suggestions, please use the comment section on the bottom of this page. Don’t forget to subscribe to our blog to get more scheduling tips & tricks directly in your inbox!

Lauren Hecker is an Oracle Primavera Cloud, Primavera P6, and Microsoft Project instructor who teaches onsite and virtual training courses. To see her next open enrollment course, please visit our calendar. To schedule an onsite or private course, please contact us!