Work Breakdown Structure (WBS): You Shall Manage No Project Without It

The major output of the decomposition processes mentioned previously is the project's Work Breakdown Structure (WBS). The WBS is a hierarchical representation and definition of the project's work as it relates to project objectives and provides the structure for managing this work through completion. As a result, it is a key tool for the project manager and is highly valued by the PMI organization.


Understand that PMI places great value and priority on the WBS. It may be the most important tool to the project manager.

Download the PMI document Practice Standard for Work Breakdown Structures from the PMI Web site ( for additional insights into PMI's view of the WBS.

Effective Techniques for Developing a WBS

Here are a few "guidelines" regarding the development of the project WBS that you will want to know for the exam:

  • All the work of the project is included in the WBS.

  • The WBS should be "deliverable focused."

  • The WBS should be developed "with the team."

  • The lowest level of the WBS is the work package or activity level.

  • Unique identifiers are assigned to each item in the WBS to allow for better management reporting of costs and resources.

  • Review and refine the WBS until all key project stakeholders are satisfied.

The level of granularity for the work package level in a WBS will vary. It depends on what level of detail the project manager plans to manage to. In other words, the level of detail that is needed for effective management and control.

In a program, or on large projects, the work package level may represent efforts in the hundreds of hours. In these cases, it is expected that the teams assigned to these work packages (or subprojects) will define the detail activities and tasks (and schedule) needed to complete the work package.

Benefits of a WBS

For good reason the WBS is given tremendous importance by PMI. More than any other project management tool, it best communicates the work of the project to all stakeholders. As a result, it offers these key benefits:

  • It facilitates understanding and buy-in of the project scope and the work effort involved from all stakeholders.

  • It enables identification of all necessary work for the project. It also reduces the number of items that "slip through the cracks," as well as the "Oh, I didn't think of that!" moments.

  • It allows each team member to easily understand how his or her work fits into the overall project, and how it impacts the work of other team members.

  • It provides a basis for staffing, cost and time needs, and decisions made for the project.

  • It keeps team members focused on the deliverables.

  • It provides a basis for future projects. A good WBS can be used as a template for future projects.

Different Types of Breakdown Structures

Although not a common problem in the IT industry, many industries utilize other breakdown structures and related acronyms that can confuse this subject. Therefore, you should be familiar with these other types of breakdown structures, as listed in Table 4.3, and how they are different from a WBS.

Table 4.3. Different Types of Breakdown Structures





Contractual WBS

Defines the level of reporting between the seller and buyer. The CWBS is not as detailed as the WBS used to manage the actual work.


Organizational Breakdown Structure

Maps work components to organizational units.


Resource Breakdown Structure

Maps work components to individuals.


Bill of Materials

Describes the physical components needed for the project.


Project Breakdown Structure

The PBS is actually the same as the WBS. This term is only used in areas where the term WBS is incorrectly used to refer to a BOM.

PMP Exam Cram 2. Project Management Professional
PMP Exam Cram 2. Project Management Professional
Year: 2003
Pages: 169 © 2008-2017.
If you may any questions please contact us: