PERT Chart

What is a 'PERT Chart'

A PERT chart is a project management tool that provides a graphical representation of a project's timeline. PERT, or Program Evaluation Review Technique, allows the tasks in a particular project to be analyzed. Although PERT charts are preferable to Gantt charts because they more clearly identify task dependencies, PERT charts are often more difficult to interpret.


A PERT chart utilizes circles or rectangles called nodes to represent events or milestones within a project. These nodes are linked by vectors, or lines, that represent various tasks. Dependent tasks are items that are required to be performed in a specific manner. For example, if an arrow is drawn from task one to task two on a PERT chart, task one must be completed before task two. Items at the same stage of production within a project but on different task lines are called parallel tasks. They are independent from one another and, although they are planned to occur at the same time, they are not dependent on one another.

Interpreting PERT Charts

A PERT chart is a visual representation of a series of events that must occur within a project’s lifetime. The direction of arrows indications the flow of the sequence of events that need to occur. Dotted activity lines represent dummy activities, which are items located on another PERT path. Numbers assigned to each task, as well as time allotments, are located inside each vector.

Benefits of PERT Charts

A PERT chart allows project managers to evaluate the time and resources required for a project. This includes the ability to track assets needed during any stage of production in the course of the entire project. PERT analysis incorporates data and information from multiple departments. This encourages department responsibility, identifies all responsible parties across the organization, improves communication during the course of the project, and allows commitment to projects that encompass the entire company’s strategic positioning. Finally, PERT charts are useful in performing what-if analysis. Different possibilities regarding the flow of project resources and milestones permit management to achieve the most efficient and useful project path.

Deficiencies of PERT Charts

The use of a PERT chart is highly subjective and subject to management’s experience. For this reason, PERT charts may include unreliable data or unreasonable estimations in cost or time. PERT charts are mainly focused on meeting deadlines that may not fully communicate the financial positioning of the project. Finally, because a PERT chart is labor intensive, the establishment and maintenance of the information requires additional time and resources in order to be effective. Continual review of the information provided, as well as prospective positioning of the project, is required for PERT charts to hold value.