What Is Work Breakdown Structure (WBS) in Project Management?

Wednesday, July 13, 2022
Michael Scheiner

Have you ever wanted to learn all about WBS, i.e. the work breakdown structure project management methodology? Sure, you have. And here you are.

WBS is widely practiced as a means of turning large projects into rational, digestible units of work that can be made into tasks and timelines. Here we’ll give a thorough overview and get you up to speed on what it is and how it works.


What is WBS in project management?

What does WBS stand for in project management? The WBS meaning here is as a form of project planning methodology. Work breakdown structure uses inverted tree diagrams, or network diagrams, to break down a project into hierarchical levels, from the main deliverable, down into work packages, and then into individual dependent and prioritized tasks.


So, what is a work breakdown structure in project management? Our definition

Our WBS definition emphasizes the ordered and hierarchical nature of the work breakdown structure. This means that as a project planning system, WBS orders tasks, activities, deliverables, milestones and goals into a strict top down order.

As noted, WBS relies on network diagram project management, which chronologically organizes parts of the overall project into manageable chunks. 

The work breakdown structure definition given here does not insist that the WMS is an agile PM approach. This is because WBS is highly predictive, in that it dictates in advance much of the project work. Agile, on the other hand, is more reactive, as in there is more rolling with the punches.

To expand on the definition of project management for WBS, the Project Management Institute, or PMI, states in its PMBOK Guide (3rd edition) that WBS is a “deliverable-oriented hierarchical decomposition of the work to be executed by the project team to accomplish the project objectives and create the required deliverables.” What’s more, most PMPs will certainly be familiar with the project WBS method.

PMBOK stands for Project Management Body of Knowledge, in case you were wondering. It’s a published guide to project management covering every step of a project lifecycle (including WBS), with the aim being to achieve a successful project outcome on schedule and within budget. You can read our article on PMBOK methodology for an overview. 

What is the purpose of a work breakdown structure?

The purpose of WBS is to plan your project from a predictive and top-down perspective, making clear the project charter and goals and proceeding to break those down into specific deliverables and the activities needed to complete them. 

One can also say that the work breakdown structure’s purpose is to present a clear plan to everyone from the stakeholders to the project team so that there is minimal uncertainty as to how, when, at what cost, and by whom, each part of the project will be done. The project management office (PMO) within your organization oversees the WBS. 

What is a WBS element?

The WBS element is part of the WBS that describes for every project task or activity some vital information like the costs, required resources, who will do it, and the scheduled start and end dates, among other things. These can all be kept in a WBS dictionary sorted by milestones and overall project scope.

What is WBS decomposition?

WBS decomposition refers to the way a final product or project deliverable is decomposed, or broken down, into smaller and smaller WBS components or work packages and groups of tasks. It refers to the collapsing of a complex project into its constituent parts.


What are the 2 types of work breakdown structure?

There are two types of work breakdown structures. They are process-oriented WBS, otherwise known as phase-based, and then there is deliverables-oriented WBS. Process-based WBS emphasizes the project phases in the second level. Deliverables-based WBS uses the second level to lay out the parts of the final product.

What are the 4 WBS levels?

There are generally 3 or 4 levels in the WBS project planning methodology. The consensus is that there are 3 main levels which are: 1) project title or goal; 2) project deliverables, phases or controls; 3) work packages or activity groups. The final 4th WBS level is then the individual project tasks which will be taken up by the team members. There are many great free templates online which you can use to create a project using WBS levels.

WBS level 1: Project goal

The first WBS level is to state your project title, goal or scope of the project. This could be the name of the final product or set of required deliverables, or a successful implementation of a new process. In process or phase-based WBS, this level will guide the stages of your project. In deliverables-based WBS, this top level will guide your individual deliverables. For stakeholders, they see this level as a project charter.

WBS level 2: Project phases or deliverables

The second level is where your project begins to understand the work ahead. In phase-oriented WBS, you use this level to map out project milestones and project stages, such as initiation, planning, execution, control and close. With deliverable-based WBS, you may break down into iterations, increments or parts of the whole. Here you should also include project costs and project scheduling into your planning process.

WBS level 3: Work packages

The third level of WBS is for work packages, which is a concept native to the work breakdown structure elements. This is for a group of tasks that are all related directly and should all be done by the same project team members within the same work period. 

WBS level 4: Tasks

Some say this is not its own level but just a drop down of the work packages in level 3. Within the work packages are the series of activities necessary to complete an iteration or deliverable. Here you can be clearer about subtasks, task dependencies, task priorities, and assignees. Also, more complex projects can extend downward with more subtask levels.  


Advantages and disadvantages of WBS for project management

Now, we’ll discuss work breakdown structure benefits. Afterward, we’ll go over the few disadvantages of the work breakdown structure.

Benefits of work breakdown structure

One of the benefits of WBS is the way it organizes big complex projects into smaller and more manageable activities. The modular components of WBS also allow for flexibility, as discrete chunks of work can be moved around and assigned or reassigned.

Another one of the advantages of work breakdown structure is that everyone involved, from stakeholders to the project team, are all very clear on their roles, their tasks, and the timeframes and costs of everything.

Drawbacks of work breakdown structure

A con of WBS is that it isn’t very agile, at least at the bigger-picture level. Since everything is hierarchized and prioritized and dependent, small obstacles can set you off course. This is why it’s always good to do a thorough project management methodologies comparison.

A second work breakdown structure disadvantage is that employees at the lower end of the project team may feel trapped in small tasks with little freedom to choose how they want to do them, and therefore people have difficulty connecting their labor to the end goal or product.


Work breakdown structure examples for project management

Let’s move into WBS project management example territory. We’ll draw from 3 industries: construction, software development, and healthcare. These work breakdown structure example cases will help you understand better how WBS is useful in real life.

Construction WBS example

A solid work breakdown schedule construction industry-wise could go something like this. The top level is a building. The next level might break that into the work packages of foundation, structure, interior, exterior. We can take one work package, say, interior, and use the next level for activities such as walls, floors, electric, plumbing. A further level down from, say, plumbing, can break it down to the kitchen, bathrooms, and every other room that will have plumbing. Construction project WBS also benefits from a process-oriented plan. 

Example of WBS for software development

While software development normally uses an agile approach like Scrum, you could have a high-level WBS plan as well working in hybrid with agile at the granular level. Perhaps the planning of a new software feature takes a phase-oriented style of WBS. The top level is the feature, but the next levels are initiation, planning, execution, control and closure. Your work packages will then follow from each phase. For example, in the control phase, you would test the various components of the feature. 

Work breakdown structure healthcare example

Let’s say a healthcare clinic needs to update all their clients’ files. They decide to create and launch a new healthcare client portal, and they must be able to mass inform everyone in their database to sign up in the portal, set up a profile, and do things like confirm their credit card or other medicare information. Theory may have to use email and social media like Facebook or even LinkedIn to contact everyone. WBS can help plan and prioritize all these disparate work packages in the best order.


How to create a work breakdown structure

Here we’ll talk about how to create a WBS. This involves identifying deliverables, breaking work down into project phases, and identifying dependencies and priorities. 

Required deliverables

The first thing you need to do as part of any project charter is figure out the project scope statement, budget and timeframe, and from there, what requirements you’ll need to produce deliverables within those constraints. You’ll make your network diagram, or inverted tree, with WBS levels. 

Break it down to project phases and work packages

The next thing you need to do to get started is to take your final deliverable and break it down into iterations or smaller deliverables that can be done by the same teams in reasonable amounts of time. Then you’ll also do a project timeline, perhaps with a Gantt chart template.

Identify dependencies and priorities

From there, you need to think about every work package and all the tasks that must go into it, paying special attention to task dependencies where some tasks must be done before others can be started. Managers should also prioritize and assign tasks. Kanban templates are useful here.


Our conclusion on WBS project management

WBS management style for project planning has its time and place. If you are using a WBS to roadmap your way to success, consider implementing a project management tool that can handle things like network diagram templates, Gantt charts, and task dependencies. 

You can check out big named CRM project management software like Microsoft Project, or more niche companies like Wrike. The right app for you is out there. 

Now, let's break those projects down!


Does every project need a WBS?

Not every project would benefit from the work breakdown structure, or WBS methodology. Projects that need to use WBS are ones that have strict hierarchies in terms of deliverables, and projects that must plan and prescribe in advance how the project work will proceed across the project team.

What is the highest element in the hierarchical breakdown of the WBS?

Work breakdown structure charts have several levels which hierarchize the WBS elements. The highest WBS element in the breakdown is the project charter, or project goal. It’s also known simply as the project name, which could be the name of a product or final deliverable. 

What is the lowest element in the hierarchical breakdown of the WBS?

In the work breakdown structure hierarchy, the lowest level includes the WBS elements that are the activities or individual tasks that are needed to complete the larger work packages which are on a higher level than tasks in the WBS order. Task dependencies and priorities are detailed above.