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, breaks down the individual tasks of a project for analysis. Although PERT charts are preferable to Gantt charts because they identify task dependencies, PERT charts are often more difficult to interpret.
BREAKING DOWN ‘PERT Chart’
A PERT chart uses circles or rectangles called nodes to represent project events or milestones. These nodes are linked by vectors, or lines, that represent various tasks. Dependent tasks are items that must 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 parallel tasks. They are independent of one another although they are planned to occur at the same time.
PERT charts are used for complex projects, and they were created for use by the U.S. Navy in 1958. Below is an example of a PERT chart.
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 indicates the flow and sequence of events required for project completion. Dotted activity lines represent dummy activities, which are items located on another PERT path. Numbers and time allotments are assigned and shown inside each vector.
Benefits of PERT Charts
A PERT chart allows managers to evaluate the time and resources required to manage 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 project and allows an organization to commit to projects that are relevant to its strategic positioning. Finally, PERT charts are useful for what-if analyses. Understanding the possibilities concerning the flow of project resources and milestones allows management to achieve the most efficient and useful project path.
Disadvantages 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 for cost or time. PERT charts are deadline-focused and 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 require additional time and resources. Continual review of the information provided, as well as prospective positioning of the project, is required for PERT charts to be valuable.