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

Introduction

Planning plays a very essential role in the success of any project. The work breakdown system (WBS) is a foundation of project planning. A work-breakdown structure in project management is a deliverable-oriented breakdown of a project into smaller components.

Thus, it is easy to estimate and manage the resources and budget for these smaller components rather than doing estimation for the whole project together.

What is Work Breakdown Structure?

The Project Management Body of Knowledge (PMBOK 5) defines the work breakdown structure as a “hierarchical decomposition of the total scope of work to be carried out by the project team to accomplish the project objectives and create the required deliverables.”

Design Principles for Work Breakdown Structure:

A good WBS should exhibit the following principles:

1. 100% Rule :

The 100% rule states that the WBS should include 100% of the work defined by the project scope and capture all deliverables, including project management. Every level of decomposition must make up 100% of the parent level. It should also have at least two child elements.

2. Mutual Exclusivity:

It is important that there is no overlap in scope definition between two elements of a WBS. This ambiguity could result in duplicated work.

3. Deliverables, Not Actions:

The best way to adhere to the 100% rule is to define WBS elements in terms of outcomes or results, not actions. Deliverables are the desired ends of the project, such as a product, result, or service, and can be predicted accurately. Actions, on the other hand, maybe difficult to predict accurately.

4. Reasonable Level of Detail:

Generally, work packages should provide work that can be completed by a team or team member within a reporting period. If status meetings are weekly, then the work must be completed within one week. Another way to determine effort is through the 8/80 rule, which states a subtask should not take less than 8 or more than 80 hours to complete.

5. Coding scheme

It is common for WBS elements to be numbered sequentially to reveal the hierarchical structure.

6. Terminal element

A terminal element is the lowest element (activity or deliverable) in a work breakdown structure (WBS). Work Packages are the lowest element in a tree structure.

Types of Work Breakdown Structure:

The two main types of Project Work Breakdown Structures (WBS) are:

1. Deliverable-oriented work breakdown structure

A deliverable-oriented WBS (also known as Product-Oriented or Noun-Oriented WBS ) decomposes the project scope into smaller and more manageable deliverables.

For example, We have a project to build a wooden deck. So, WBS can be:

2. Phase-oriented work breakdown structure

A process-oriented WBS (also known as Process-Oriented or Verb-Oriented WBS ) defines what process steps need to be taken to deliver each of the project deliverables.

For example, the phases in the project lifecycle: initialization, planning, execution, control, and closure. In the following diagram, WBS represents these phases.

Steps to create Work Breakdown Structure:

1. Determine and describe the project statement.
2. Highlight all the necessary phases of the project.
3. Create and list the deliverables.
4. Divide the deliverables into manageable tasks.
5. Assign responsibilities and clarify roles.
6. Track the progress of a project.
7. Identify risk.

Let us conclude why we should use WBS in Project management.

There are several reasons why breaking down a large project is beneficial. Some of them are,

1. It helps you with cost estimation.
2. It helps you to establish dependencies.
3. Provides a visual representation of all parts of a project.
4. Identify the risks.
5. Improves productivity.
6. Helps to identify resources.
7. Assign responsibilities and clarify roles.
8. Helps to track the progress of a project.