5th Edition PMBOK® Guide—Chapter 5: Work Breakdown Structure

1. Introduction

The Work Breakdown Structure is a fundamental tool of project management which is formed as an output of the process 5.3 Create WBS. It is one of the three elements of the scope baseline.

Table 1.  Three Elements of the Scope Baseline

Element Name Process
1. Project Scope Statement Output of 5.3 Define Scope
2. WBS Output of 5.4 Create WBS
3. WBS dictionary Output of 5.4 Create WBS

The work breakdown structure can be pictured like an organizational chart, with the highest level being the project itself, and the various levels under that consisting of increasingly more detailed breakdowns of the scope of the project.

For example:

Although it can take the form of an organizational chart, it does not show who does the work, but simply displays the hierarchy of the various levels of decomposition of the scope.

2. Decomposition technique

The techniques of decomposition means subdividing the project scope and project deliverables into smaller, more manageable components to the level of work packages. Here’s how the project is broken down through the decomposition process.

Figure 1. Work Breakdown Structure Levels (from program to deliverables)

a. Programs are groups of related projects.

b. Projects can sometimes be broken down into distinct phases.

c. Major deliverables are first identified within each phase.

d. That work which can be outsourced to a contractor is referred to as a subproject.

e. Deliverables are broken down from the major deliverables.

Figure 2. Work Breakdown Structure Levels (from deliverables to activities/tasks)

f. Once deliverables are identified, for large-scale projects planning packages are identified which are basically fill-in-the blank packages for work that has not yet been identified, but will be in the course of progressive elaboration.

g. A control account is a summary level in WBS one level above a work package. Once a group of work packages under a control account are completed, some sort of monitoring & controlling activity is done here to make sure the project is proceeding according to plan.

h. Work package is the lowest level in a work breakdown structure which both defines specific deliverables and those resources (people, equipment, etc.) assigned to complete the work (through the WBS dictionary).

i. The work package, which specifies the smallest unit of deliverables, is further broken down into activities during the process 6.1 Define Activities. In some companies with large work packages, the activities can be further broken down into …

j. Tasks, but this is sometimes a confusing term because some companies have tasks at a higher level than activities. So for the purpose of the PMP exam, just focus on activities as the steps taken to produce the deliverable within each work package.

3. Work Breakdown Structure—What is it for?

The work breakdown structure is to the project what the blueprints are to the product, a guide for getting it realized. Although I have listed the WBS under Scope Management, because it helps prevent unnecessary changes to the project (also known as preventing scope creep), but it helps in EVERY knowledge area.

Project Management Area How does WBS help the Project Manager?
4. Integration Management Helps the project management team see the entire project laid out in a single diagram.
5.. Scope Management Helps prevent unnecessary changes.
6 Time Management Helps create realistic basis for estimating schedule.
7 Cost Management Helps create realistic basis for estimating costs.
8 Quality Management Helps focus work on what needs to be done at the right time, increasing quality. If problems do occur, assists process improvement by making it easier to isolate root cause.
9 HR Management Creating the WBS as a team helps build the team and creates a sense of active participation that lasts throughout the project.
10 Communications


Helps explain the project to stakeholders and helps project team members from different functional areas to cooperate with each other.
11 Risk Management Makes it easier to identify risks by making the work steps and work sequence easier to understand.
12 Procurement


Helps identify those work packages which cannot be done with current company resources and/or expertise level.
13 Stakeholder Management Helps manage stakeholder engagement by helping to explain the impacts of changes suggested by stakeholders.

So, in conclusion, with all of these benefits, why wouldn’t you make creating a WBS one of the key parts of your planning process?


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