Work Breakdown Structure (WBS): An Overview, Uses, Software

A work breakdown structure (WBS) is a project management tool that decomposes the total scope of work required to deliver a product, service, or project into smaller, more manageable components. A WBS is a snapshot of all the work stakeholders and teams need to complete to successfully finish a project. You’ll use it as a basis for planning projects and identifying and organizing project phases and deliverables.

What is a work breakdown structure?

A work breakdown structure (WBS) is a useful and widely-used project management tool. You’ll use it to translate strategies and overall objectives into specific goals, schedules, workflows, and action plans.

A work breakdown structure (WBS) is a hierarchical view of your project’s scope and is used to organize and plan projects, programs, and portfolios. You can organize each element in the WBS into scheduled activities that will make up the performance measurement baseline (PMB) to help define the deliverables for your project.

Why use a WBS in project management?

You’ll use work breakdown structures to identify the project tasks that make up the critical path of your project. This enables you to plan your resources, timelines, and priorities. You’ll also have a clearer picture of the risks the project may face as it progresses.

Project planning, scheduling, and budgeting

The top level of your WBS represents the project's final deliverable, or end product. It represents the project scope statement. The lower levels break down the scope into more detailed deliverables and tasks. All these sub-elements can have time and cost estimates associated with them. When combined, they form a total estimate of what’s required to complete the project within its defined scope. This makes it possible for you to plan, schedule, and form budgets based on the details of the project rather than relying on high-level guesstimates.

Risk management, resource management, task management, and team management

The work breakdown structure lets you dissect the project to understand how it all fits together and create a Gannt chart that provides clear focus and critical path requirements.

When you create a WBS, you’re required to think through each activity in detail to define all the work necessary to complete it. In doing so, you’ll identify risks that may impact your project. These can go on the risk register, and you can then form an appropriate project risk plan. 

You will also identify the resources needed to complete each task, which will help you plan how many people you need on your team and when you need them. This will help you manage your team during the project life cycle because you can assign each task to a team member with the required expertise. 

Here are five examples of how you’ll benefit by using a WBS in your project:

• Better communication with your team members regarding tasks

• Clearer definition of the deliverables that need to be produced during each project stage 

• More accurate time estimates for each task because you can see precisely what needs to be done for each step of the project

• Easier identification of critical path items, so you can take steps to reduce risks to these tasks (e.g., add resources or assign another team member to help complete it)

• More easily identify which tasks should be done by whom because you can see where the expertise is needed most.

Types of WBS

The two types of work breakdown structures are process-oriented and deliverable-oriented. Each has its advantages and disadvantages.

1. Process-oriented WBS

A process-oriented WBS decomposes work into the processes needed to accomplish it, such as requirements, design, development, and testing. The advantage of this type of breakdown structure is that it clarifies what needs to be done and who will do it. It also makes it easy to assign resources and estimate time because they can be assigned at each level of the structure. Process, or phase-oriented WBS, is often preferred by clients as they provide clear milestones.

2. Deliverable-oriented WBS

A deliverable-oriented WBS decomposes work into tangible products or services, such as database schema, and user manuals. The advantage of this type of breakdown structure is that it gives an overview of the deliverables required for a project. This type of WBS is most appreciated by project teams and management.

How to use a work breakdown structure

You use work breakdown structures to define and organize the total scope of a project. The WBS is a hierarchical tree structure.

Work packages

A work package is the lowest level in the WBS. It represents the work needed to accomplish a specific deliverable. Once completed, it should be possible to physically hand over the work package to another person.

Planning packages

Planning packages are used as an independent planning horizon for one or more work packages that will be completed in the future. They help to summarize the project plan at different levels.

Control accounts

Control accounts help control costs and schedules on projects with very large budgets or when a large part of the budget or duration applies to only one or two major deliverables. Control accounts function like work packages with some additional requirements. Control accounts are usually created for major parts of the project, such as phases and key deliverables.

Deliverable-based work breakdown structure

A deliverable-based work breakdown structure is a hierarchical tree structure of the project and its components. It shows the connection between the project deliverables and the work to be done. The deliverable-based WBS organizes the work horizontally as related activities, providing a view of the entire project from start to finish.

Phase-based work breakdown structure

A phase-based WBS is a project management philosophy that breaks projects down into phases, each of which has its own purpose and features. The phases are usually broken down into smaller tasks, which are typically further broken down into simpler tasks. 

What are the elements of work breakdown structure?

You can imagine WBS as a series of levels that you unpack. Each level represents a more detailed view of the project work. It is a hierarchical decomposition of what’s required to meet project objectives.

• WBS dictionary: The WBS dictionary documents each component with its definition, estimated effort, and performance measurements.

• WBS levels: The WBS levels provide context for each portion of the project.

• Control accounts: Control accounts provide a way to manage cost and schedule at higher levels in projects that are very large or complex.

• Project deliverables: Project deliverables are grouped into work packages.

• Work packages: Work packages describe activities that can be planned, scheduled, and controlled by one person.

• Tasks: Tasks are work packages broken down into smaller activities so they can be scheduled, monitored, and controlled by one person.

How to make a work breakdown structure

This structure of a WBS helps everyone on the team understand what needs to be completed, who's responsible for each task, how tasks relate to one another, when things should be done and how much they will cost. This is how you make a WBS:

1. Gather critical documents: Gather critical documents, including the project charter, the project management plan, and the risk register.

2. Identify key team members: Review the organizational charts and consider what information you need from each person.

3. Define level 1 elements: List all deliverables or phrases associated with the project.

4. Decompose (breakdown) elements: Break down each item of work into subtasks that can be estimated and scheduled.

5. Create the WBS dictionary: After decomposition, a WBS can be represented as an outline or a diagram.

6. Create a Gannt chart schedule: The schedule is one of the most important components of a project management plan and will be used to monitor progress throughout the life of the project.

Other use cases of breakdown structure

A breakdown structure is a hierarchical decomposition of the project deliverables. The other types of breakdown structures include resource, risk, and organizational breakdown structures.

Resource breakdown structure

The resource breakdown structure (RBS) is used to identify all of the resources required to complete each work package in the WBS and for the project. It can be developed by starting with the work packages in the WBS, then collecting all of the resources needed to complete each work package, and finally organizing them into a hierarchical structure based on their similarity or specialty.

The goal of the RBS is to ensure that all necessary resources are available to carry out the project and that there are no conflicts in their usage, which could delay the project.

Risk breakdown structure

A risk breakdown structure (Risk BS) is used to organize risks into categories and subcategories in a way that helps you manage them effectively. Risk categories may be defined by type, risk source, or other means deemed appropriate for your project. 

A risk category would be something like "cost," "schedule," "quality," or "scope." Risk subcategories would be more specific risk types within each category. For example, under cost risks, you might have subcategories like "labour rates," "material costs," or "budget overruns."

Cost breakdown structure

A cost breakdown structure (CBS) shows the estimated cost of each element of the project. For example, the cost of a website is made up of hosting, programming, design, and content creation. The CBS makes it easier to estimate and control costs.

Organizational breakdown structure

An organizational breakdown structure (OBS) shows how roles are assigned within an organization. For example, a medium-sized online business might have a chief technology officer, chief operating officer, chief executive officer, and other roles, each with different responsibilities.

WBS software tools

Many free and paid software tools can help you create WBS for your projects. Each has its strong points, and project managers often have a preference based on what they like, from function to the user interface. Here are some common WBS software tools:

EdrawMax

EdrawMax is a versatile and capable diagramming application. It covers all aspects of WBS, including flowcharts to floor planning to business process diagrams. It's best suited for people who need a feature-rich tool that covers a wide variety of use cases.

Lucidchart

Lucidchart is a cloud-based visual collaboration tool that allows teams to work together on the same diagram with real-time updates and live chat. Lucidchart provides a simple interface that enables you to create professional diagrams without prior experience.

SmartDraw

SmartDraw is a browser-based tool. It helps you draw flowcharts, organization charts, mind maps, project charts, and more.  It’s useful for visualizing projects and individual aspects of a project.

Visual Paradigm

Visual Paradigm is an extensive software suite that offers everything from project planning to source code management and test case design. This application is best suited for professional developers and managers working on large enterprise projects.

MindView

MindView is designed specifically for project managers and business professionals who create mind maps to plan projects, brainstorm solutions, and present ideas visually. Mindview’s collaborative tools allow team members to work together on project planning.

Creately

Creately is an online diagramming application that makes it easy to draw flowcharts, organizational charts, mind maps, and other diagrams online. Creately comes with features such as smart drawing aids that automatically align shapes while drawing flowcharts or other diagrams. You can also use it to collaborate with your colleagues in real time while working on a project together.

Want to learn more about project management?

Project management is an in-demand skill, with employers looking for experts who can lead projects that drive positive business outcomes. 

If you are ready to learn more about project management, explore the Google Project Management Professional Certificate, a six-course program designed for project managers at all levels.

Frequently asked questions