Joseph Phillips, PMP: Creating the Work Breakdown Structure (WBS)

The WBS is a decomposition of the project scope statement. It is a deliverables-oriented document that visualizes all the things the project will create. It is not, and I stress the word not, the activity list. The WBS takes the project scope statement and breaks it down into the deliverables the customer is expecting from the project. It organizes and catalogs the project deliverables.

The smallest item in the WBS, that is the lowest decomposed deliverable, is called the work package. I know what you’re thinking (maybe). If the WBS is not about activities then why is it called a Work Breakdown Structure – and why is the smallest element a work package? Good question! When we think of “work” we often think of labor – like I’m working on a report. Work can also be a noun – like the works of Mozart or the works of Picasso. When it comes to the WBS you should think of work as a noun rather than as a series of activities.

The process of creating the WBS should involve the project team and the project’s key stakeholders. Yes, the key stakeholders should be involved in creating the WBS. It’s important to involve the project stakeholders, as this promotes additional project buy-in and it helps the stakeholders see the depth of deliverables that are included as part of the project.

The process of decomposing the project scope begins with the high-level project deliverables: such as the project management deliverables, the foundation, the framing, and so. Then each top tier deliverable is decomposed again and again until you’ve reached the smallest level of deliverables – the work packages. Here’s a tip: you know that you have decomposed the project deliverables deep enough by using the 8/80 Rule. The 8/80 Rule means that each work package can be completed with not less than 8 hours of labor and not more than 80 hours of labor.

Just as each project scope statement is unique so too must each WBS be unique. Having said that, it is acceptable to use a WBS from a previous similar project and adapt it to your current project as a WBS template. Some organizations have a consistent level of deliverables with all of their projects so they use a pre-populated template to reflect these “every project” deliverables. For example, you might create a template that reflects your project management plans, quality control charts, and expected reports that the project will generate.

The numbering system is known as a code of accounts. Each WBS deliverable is identified and can be tracked by time, cost, and other metrics using the code of accounts. The code of accounts can also help facilitate communication between the project manager and the project team. Imagine trying to identify which bedroom a contract is discussing in a four-bedroom home construction project. The WBS code of accounts can point all parties to the exact deliverable using the numbering system for each component.

Along with the WBS you’ll create a companion document called the WBS Dictionary. The WBS Dictionary is a document that defines all of the details for each of work packages. It defines what the work package is, the owner of the work, contract information (if warranted), technical references, and cost information for each work package. The project scope statement, the WBS, and the WBS dictionary all serve as the project’s scope baseline.

The approach that I’ve outlined here is the most common – deliverables are decomposed into smaller deliverables down to the work packages. There is, however, another approach which is just as acceptable – to decompose the phases of the projects into the work packages. For example, an IT project may have identified phases such as requirements gathering, development, testing, training, and roll-out. A project team could elect to decompose the project by these phases rather than by the major deliverables of the project. In either method the project manager will be using the WBS throughout the project. The WBS is needed in order to do five key project management activities:

• Cost estimating – the prediction of how much the project will cost
• Cost budgeting – the actual allotment of monies to create the project deliverables
• Resource planning – the determination of what materials and labor will be needed to create the project deliverables
• Risk management planning – the identification of project risks and how the risks will be managed
• Activity definition – the activity list is created as a result of the WBS