Work Breakdown Structure

13.06.2017 |

Episode #8 of the course Introduction to Project Management by John M. Smith


Welcome to the eighth lesson of the course. Today, we will learning about the Work Breakdown Structure, an essential tool for any project that has a level of complexity.

The Work Breakdown Structure, often abbreviated as the WBS, is a visual tool designed to help define and communicate the resources portion of the project plan. It takes the project’s deliverables and breaks them down to show the resource utilization, essentially bringing high-level assignments to a level that allows for control and monitoring of individual tasks. Being a resource map for the project, it is useful to the Project Manager and their team as both a management and reporting tool.


Building a WBS

A WBS is constructed with a top-down approach. It begins with deliverables and splits using a “family tree” style hierarchical graphical interface, typically depicted as a PERT chart. PERT, or Program Evaluation Review Technique, is an analysis and organization tool used primarily in project management for WBS purposes.

Some projects may be complex or lengthy enough that several WBS charts are utilized, separated by factors such as lifecycle phase or milestone. Each belongs to the root WBS but is isolated or layered separately for ease of use. WBS charts can be used to show information that helps determine statistical elements like workload balancing, financial impact, and priority. This is done using numbers, colors, and other visual cues. Percentages can be assigned to each task indicating different information, such as percentage of the project (hours or financial) or percent complete.

Let’s build a WBS for our example of adding ventilation to a bathroom. We will focus on resources and budget.

In our example, we have broken the deliverable down into four basic tasks and broken those tasks into steps indicated with their own individual budgets. I kept these simple with fairly linear steps, but a task might break into several branches, which themselves can break into branches. The color-coded steps indicate who is responsible for them. This makes it easy to see that our red-coded team member, “Dad,” has the most responsibility. This is important for management because if an unexpected activity is added, it is quickly determined that Dad is not the most available team member and perhaps another person should be utilized. We also color-coded our vendor member, the electrician. A Project Manager might choose to color all vendors the same to indicate their special status, or if they’re going to be utilized often for a variety of tasks, they might be treated more like a regular team member, and perhaps another indication could be used to indicate that they’re a cost center.


The 80-Hour Rule & Other Guidelines

When deciding on what level of detail to break a task down into, it is helpful to have guidelines to follow. The “80-Hour Rule” states that any task that takes more than 80 hours to complete should be broken down into smaller tasks. Some projects modify this rule to be stricter, limiting tasks to short-term measurements like work shifts. Another guideline is to limit tasks to an individual person, department, or job function. What is important is choosing a method that meets the needs of the project. That may mean some tasks are broken down more than others, depending on their importance or complexity.


Critical Path Management

Managing tasks by their importance is known as Critical Path Management. The critical path is defined as the series of tasks that will cause the project to stop, prevent further work from being done, and/or incur extra costs. Knowing the project’s critical path is important for prioritizing, problem solving, and predicting problems before they happen. The critical path can be marked on the WBS using colors, shapes, or other visual cues.



A Work Breakdown Structure is an important Project Management tool that acts a map for the project and provides a visual aid to communicate specifics and manage aspects of the project that would otherwise be more difficult. Tomorrow, we’ll learn about an indispensable Project Management tool: the schedule.


Recommended reading

Work Breakdown Structure


Recommended book

Practice Standard for Work Breakdown Structures by Project Management Institute


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