Work Breakdown Structure

Work Breakdown Structure is simply a tool that breaks the work down into a structure. All the project scope should be included in a WBS, and we call it a 100% rule.

The WBS provides a graphical representation or textual outline of the project scope.

In WBS, much larger tasks are broken down into manageable chunks of work. These chunks can be easily supervised and estimated.

In project management, a work breakdown structure is a deliverable-oriented decomposition of a project into smaller components. It may be a product, data, a service, transition, or any combination.

Work Breakdown Structure is a project planning tool that is done after the Project Charter is approved. It is a hierarchical structure of overall project work. It is the same like

  • PBS – Product breakdown structure that is a hierarchy of products
  • OBS – Organization Breakdown Structure – An organizational Chart and
  • CBS – Cost Breakdown structure, Budgeting of a Project

Here you can: Download Work breakdown structure Template 

Why Work Breakdown structure?

Every single project you manage must have a work breakdown structure as you cannot afford to misunderstand this important project management tool.


otherwise, the project may take longer, elements may slip through the cracks, and the project will be negatively impacted in any case.

Work Packages Identification

Work packages are the lowest part of any WBS; you can identify that it is reached when they include deliverables that.

  1. It can be realistically and confidently estimated.
  2. It can be completed quickly.
  3. It can be completed without interruption (in other words, without the need for more information).
  4. It was maybe outsourced or contracted out.

The lowest level element (or deliverable) is an element in a work breakdown structure (WBS), which is not further subdivided and is also called a terminal portion. A terminal element is sometimes called a work package but always remembers the two terms ( i.e., the terminal element and the work package ) are not synonymous in a WBS.

As we see the formal definition of a work package is that it is a unit within a WBS at the lowest level of its branch or a group of related tasks at the same level within a WBS.

The followings are the characteristics of a  work package  :

  •  It should be small to be managed independently but Should  be large enough to be correctly estimated,
  •  It has a meaningful  and measurable deliverable.
    Size of a work package: there is no hard and fast rule, but there is a general ‘8/80 Rule’ that says that all the  Work Packages should be more than 8 and less than 80 hours in duration.

It plays some role in deciding the detailing level and the time between status reports. For example, if one team reports bi-weekly, the largest work package then should be 80 hours. Then at meetings, it becomes easier tracking delays.

How to Draw a Work Breakdown Structure

Before we start, make sure that project objectives and scope is crystal clear and is signed off by respective stakeholders.

We follow the 100% rule while going to draw a WBS; it means we have to cover the whole project scope.

As a Project Manager, you should brainstorm your team. Posted and sticky notes should be used on a whiteboard as you can move around it quickly. This buy-in will help as those are guys going to perform and get you the results. After the team has contributed sufficiently, then sit on MS Project, Primavera P6, or any software and draw the template. Make sure all the scope is covered. Send this document to the team for their feedback again (if any) comply and finalize it. Let’s summarized the pre-requisites

  1. Team buy-in must be those are the one going to perform for you.
  2. The first level is completed before the project is broken down further.
  3. Each level of the WBS is a smaller piece of the level above.
  4. The WBS includes only deliverables that are really needed.
  5. Deliverables not included in the WBS are not part of the project.

Organizing the WBS

There are no hard and fast rules to create a WBS; it can be created by;

  1. Constituent Products
  2. Subsystems
  3. Projects
  4. Process Phases
  5. Time Phases
  6. Geographic Areas
  7. Organizational Departments
  8. Mix Up of above

If you ask different people to draw a WBS and they may come up with a different idea, and all can be correct. But the factor is they must have to cover all the scope of that project – Nothing extra, nothing less.

The criteria to choose from above is, for example, breakdown through Organizational Departments is the best approach for functional organizational structure based firms. Constituent Products are the best for manufacturing firms.

You can use it as per your organization’s standard templates. No harm to choose any. All are the best approaches.

Usually, a WBS is Tree Structure View, but you can have it in tabular form as well.

Example of a WBS

Work Breakdown structure sample

This is a general example of a WBS of a Project. Here, if you see a Project is Broken down in manageable chunks. It is a mix up of phases, deliverable, and sub-projects. You need to breakdown unless you get work packages. Usually, you get it after the fourth level, and for a complex project, it goes maximum sixth level.

The depth of the WBS is dependent upon the size and complexity of the project and the level of detail needed to plan and manage it.

A simple example, let say you are managing a wedding. Here the wedding is the project. Next, you will break it down to Reception, Refreshment, Ceremony, and Departure. Then you can breakdown these into further levels like for Refreshment you can put Planning, budget, Menu and catering services. The same goes for others. I Hope it is clear.

Here, you can download Primavera P6.

Work breakdown structure in Primavera P6

Typically, level 2 defines the way that on what basis you are going to breakdown the project work like in below example, we are going to process phases that is

Work Breakdown structure Level 2

the same way you can do area wise. This is completely your personal choice.

In the next Levels, Initiation will be further divided like Define Project goals, Contractors buy-in, Access feasibility. In Planning, you can go for risk Analysis, schedule tasks, set budgets, etc. Same for others unless you reached to respective work packages.

I hope I am transparent in it. Any questions, you can comment below.

Outputs of Decomposition

Following are the outputs after decomposing of a project work

WBS:  A clear WBS with unambiguous identifiers

WBS Dictionary: A WBS Dictionary contains descriptions of each WBS component like;

  • Identifiers
  • Statement of Work
  • Milestones
  • Accountable Entity

In the case of larger projects with hundreds of activities, and it may be challenging to keep track of all the activities. One very important tip is to create a WBS dictionary, which includes the short description ( of summary and detailed activities), numeric identifier ( 1,1.1,1.2,2,2.2.2, etc..) for each of them and the estimated effort as well. You can also enter your WBS dictionary into any of the readily available software tools; the tool helps to keep track of changes to the WBS.

Scope Baseline: Scope baseline contains an approved Scope Statement, the WBS, and the WBS dictionary.

Characteristics of a Breakdown Structure

  • All the significant deliverables are easily identifiable.
  • Identifiers are mentioned in each WBS component. We call it Unique WBS Identifiers.
  • A WBS should be broken down at the lowest level. We call it a work package. You may not consider it for smaller projects.
  • All project scope is covered.
  • Breakdown chunks are mutually exclusive.
  • WBS is adaptable and is compatible with Agile Management.
  • Most commonly, the project title goes at the top of the WBS.
  • The first level is usually the same as the project life cycle.
  • The following levels break the project into smaller pieces.
  • This is a top-down effort to decompose the deliverables and the work required to produce them.
  • The complete scope of the project (product, project, and management efforts) are included.
  • Each work package consists of nouns (things) rather than actions.

Pitfalls of WBS

  • A WBS is not an Organization hierarchy
  • Deliverables are not activities or task
  • A WBS is not a Plan or Schedule
  • WBS update required a proper change control system
  • Level of Work Package details should be at a proper level

Characteristics of WBS Tasks

  • Definable: Tasks are defined like Installation of Pipe
  • Independent: Tasks are Independent, which means the accountable person is identified for the specific task.
  • Estimable: You can estimate time and cost
  • Measurable: Progress quickly tracked
  • Adaptable: You can add or remove any chunks like you can adjust change order or variation orders easily.

Benefits of Work Breakdown Structure

  • Work breakdown structure is a result of a common understanding of all the work required to deliver a project.
  • It helps to avoid scope creep and gold plating 😉
  • The proper numbering system in WBS gives to define how many hours or if someone purchases something, then we can trackback that code to understand where the money has been spent.
  • It gives the idea of Milestones of a project. Milestones are the important events of any project with zero duration. For example, Project start, project end start of Testing and Commissioning are the key milestones. A milestone is often represented as a Diamond shape.
  • It helps prevent work from slipping through the cracks.
  • It provides the project team members with an understanding of where their pieces fit into the overall project management plan.
  • It facilitates communication and cooperation among team members.
  • It helps prevent unwanted changes without a proper change management system.
  • It provides a basis for estimating staff, cost, and time.
  • It gets team buy-in and builds the team.
  • It helps people get their minds around the project.
  • It provides the framework for all deliverables throughout the project life cycle.
  • It develops a clear vision of the end products or outcomes to be produced by the project.

Wrap Up

A good work breakdown structure is a combination of the tasks that are mutually exclusive and the whole project scope is covered. Most project managers make mistake while covering the scope – avoid it.

Major roles of WBS in defining the project scope is it decomposes the overall project scope into clearly defined deliverables, defines the scope of the project in terms that the stakeholders can understand, provides a structure for organizing information regarding the project’s progress, status, and performance supports tracking of risks to assist the project manager in identifying and implementing necessary responses.


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4 thoughts on “Work Breakdown Structure”

  1. Work breakdown structure explained in this blog is really helpful. I just shared with my friends to help them with their upcoming assignment.

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