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. It is a snapshot of all the work stakeholders and teams need to complete to finish a project successfully. You’ll use it to plan projects and identify and organise project phases and deliverables.

What is a work breakdown structure?

A work breakdown structure (WBS) is a widely used project management tool. It helps you 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 used to organise and plan projects, programs, and portfolios. To help define your project's deliverables, you can organise each element in the WBS into scheduled activities that will make up the performance measurement baseline (PMB).

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 allows you to plan, schedule, and form budgets based on the project details 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 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

• A 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. This type of breakdown structure has the advantage of clarifying 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 it provides 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. Project teams and management most appreciate this type of WBS.

How to use a work breakdown structure

You use work breakdown structures to define and organise 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 physically possible to 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. They help to summarise the project plan at different levels.

Control accounts

Control accounts help control costs and schedules on projects with huge 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 project parts, 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 organises 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 with its purpose and features. The phases are usually broken down into smaller tasks, 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 dictionary documents each component's 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 very large or complex projects.

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

• Work packages: Work packages describe activities that one person can plan, schedule, and control.

• Tasks: Tasks are work packages broken down into more minor activities so one person can schedule, monitor, and control them.

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 organisational 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 work item into subtasks that can be estimated and scheduled.

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

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

Other use cases of breakdown structure

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

Resource breakdown structure

The resource breakdown structure (RBS) is used to identify 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 organising them into a hierarchical structure based on their similarity or speciality.

The goal of the RBS is to ensure that all necessary resources are available to carry out the project and that their usage runs smoothly, which could delay the project.

Risk breakdown structure

A risk breakdown structure (Risk BS) organises risks into categories and subcategories to help you manage them effectively. Risk categories may be defined by type, source, or other appropriate means for your project. 

A risk category would be '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 project element. For example, the cost of a website includes hosting, programming, design, and content creation. The CBS makes it easier to estimate and control costs.

Organisational breakdown structure

An organisational breakdown structure (OBS) shows how roles are assigned. 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, from flowcharts to floor plans to business process diagrams. It's best suited for people who need a feature-rich tool for 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. Its simple interface enables users to create professional diagrams without prior experience.

SmartDraw

SmartDraw is a browser-based tool. It helps you draw flowcharts, organisation charts, mind maps, and project charts.  It’s useful for visualising 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 best suits 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 drawing flowcharts, organisational charts, mind maps, and other diagrams easy. Its smart drawing aids in automatically aligning 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 for project managers at all levels.

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