What is a Work Breakdown Structure (WBS)?

Work Breakdown Structure: a complete guide

It is becoming increasingly common to encounter projects of monolithic proportions, which at first glance seem difficult to implement; but not unmanageable thanks to the use of a work breakdown structure.

What is a Work Breakdown Structure and what does it consist of?

A Work Breakdown Structure is a description of the work that will be done for a project.

It is a simple and methodical way to organize and understand the scope of the project. The approach allows companies to look at a project from the top down and break it down into smaller tasks and subtasks that will help complete the project.

By definition, projects are global tasks that are far from routine, that always involve risks, and are furthermore wrapped in a tight time and cost corset. As a project manager, you receive a project order that contains the project title, objectives, start and end dates and specified costs. Nothing more. And often it is not even that, but simply an instruction, "Do it!"

So it's an instrument that the project manager has at their disposal to get the project to a successful conclusion.

Indeed, for a project manager, the first big challenge is to get an overview of the overall task. What exactly must be done to achieve the objectives? When exactly do we have to do what needs to be done to meet the deadlines? What are the priorities? And which experts do I need for support? The answer to these questions is supported by the "Work Breakdown Structure" project management method.

What are the objectives of the Work Breakdown Structure (WBS)?

A WBS has three main objectives:

  1. Describe the division or breakdown of work into tasks.
  2. Plan the work to be done for the project.
  3. Estimate the cost of each task.

The degree of detail in a work breakdown structure depends on the level of precision required in the estimates and the level of tracking required against those estimates. Projects that have a very low tolerance for time or cost variances generally require a more detailed Work Breakdown Structure, and diligent tracking of work progress and cost against the work breakdown structure. This type of project is common in the construction and engineering sectors.

In contrast, projects in industries such as media and advertising, software, and IT infrastructure tend to be one-of-a-kind, and productivity depends on the experience and qualifications of the person performing the task. Therefore, these industries use a Work Breakdown Structure to approximate the size of a project, not to track the progress of that project in detail.

Creating a WBS is an intensive process that typically takes place over a long period of time and requires collaboration and input from a wide variety of people. This article describes how you can use WBS enhancements to meet your needs for estimating and tracking.

But before you can think about creating your work breakdown structure, you need to define the type.

What are the types of work breakdown structures?

There are two types:

1. Deliverable-based work breakdown structure

As the name suggests, this WBS will focus primarily on the project deliverables. This can be a physical product, digital content or an online service (website/mobile app). It easily links the project scope to each deliverable. Project managers often use this WBS template to create project budgets, resource estimates, etc.

A real example would be a WBS sheet for automotive manufacturing. Interior, body and electronics form the first elements of the hierarchy. Then you can link the appropriate components that you need to make for each of these heads.

2. The process-based work breakdown structure

This type of WBS tool will define your project in terms of work phases, functions and steps. You can easily assign different steps to different skills and disciplines. This helps identify the type of tools you need, the skills required, etc.

One such example is a WBS draft for a mobile application development project. Here, application development phases such as configuration, system testing, critical systems review, and user systems form the top-level hierarchy. You can now link other phases to the appropriate headers.

Whatever type of work breakdown structure the project manager adopts, they will need to follow at least six steps.

The 6 steps of the Work Breakdown Structure in detail:

1 - List all tasks

The first step in creating a work breakdown structure is to create a comprehensive list of all the tasks to be performed on the project in the form of work packages. This task should not be done by one person (e.g. the project manager) in a quiet room, but by a team. In practice, the brainstorming or mind mapping method is suitable for this purpose.

2 - Create task groups

The defined tasks are grouped according to areas or time frame. The best method of sorting depends on the content of the project and must be defined on a case by case basis.

3 - Define work packages

After grouping, the identified tasks are summarized into work packages. From the outset, it is important to specify the granularity you wish to use so as not to get lost in details. The work breakdown structure can be detailed, but in this case, the same level of detail must be used in all the phases of the project.

4 - Assign responsibilities to work packages

If the work packages are defined in terms of headings and their place in the hierarchy, it is time to get down to business: Who does what? The assignment of responsibilities to work packages is done in the team with the technical experts. Each manager must be committed to their task. And above all, they must have the necessary time and know-how. If not, the appointment of another employee must be considered.

5 - Define the start and end dates of the work packages

Once the responsibilities are defined, the work packages are planned by defining start and end dates. It is important to consider where priorities lie and which work packages are interdependent. Which activities should be carried out one after the other, which ones can be paralleled, and which ones may not be so important and can therefore be postponed?

6 - Document the created work breakdown structure and assigning unique numbers for the work packages

The last step is the documentation of the created work breakdown structure. In this step, each subtask also receives a code name - the work package number. This ensures a fixed place in the work breakdown structure, and clearly identifies the work packages.

There are many mapping possibilities. Whether in the form of an Excel list, a beautifully prepared graphic or a simple  sticky note on a whiteboard, everyone can decide for themselves which method of presentation is the most appropriate. The need for maintenance, which is necessary in any project, should not be ignored.

It is important that each revision of the work breakdown structure is versioned to avoid the hassle of having several different project plans from the start.

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