A PERT (Program Evaluation Review Technique) chart is a project management tool used to schedule, organize, and coordinate tasks within a project. It was developed in the late 1950s by the U.S. Navy for the Polaris submarine missile program.
A PERT chart presents a visual illustration of a project as a network diagram consisting of numbered nodes (either circles or rectangles) representing events, or milestones in the project linked by labeled vectors (directional lines) representing tasks in the project. The direction of the arrows on the lines indicates the sequence of tasks.
The key elements of a PERT chart include:
- Tasks: These are the steps or activities that need to be done in the project.
- Duration: This is the time it takes to complete each task.
- Dependencies: Some tasks cannot start until others are completed. These relationships are called dependencies and are represented by the arrows in the chart.
- Milestones: These are significant events in the project that are represented by the nodes in the chart.
- Critical path: This is the longest path from the start to the end of the project, taking into account task dependencies. It represents the shortest time in which the project can be completed. Any delay in the tasks along the critical path would delay the whole project.
By creating a PERT chart, project managers can evaluate the time and resources required to complete a project, identify the critical tasks that need to be prioritized to stay on schedule, and anticipate potential problems based on task dependencies.
Example of a PERT Chart
Let’s consider a simple project, such as planning a small company event, and create a basic PERT chart for it.
The tasks might be as follows:
- Select the date (2 days)
- Book the venue (5 days)
- Plan the menu (3 days)
- Hire a caterer (4 days)
- Send invitations (2 days)
- Track RSVPs (7 days)
- Hold the event (1 day)
The dependencies might look something like this:
- You can’t book a venue until you’ve selected a date.
- You can’t plan the menu or hire a caterer until you’ve booked a venue.
- You can’t send out invitations until you have a date and venue.
- You can’t track RSVPs until the invitations are sent.
- You can’t hold the event until all of the previous tasks are complete.
A PERT chart for this project would start with “select the date” at the beginning and “hold the event” at the end. Between these two points, the other tasks would be laid out according to their dependencies. The critical path here would include all tasks, as one follows another without any possibility to be executed in parallel.
The chart would visually demonstrate the sequence of the tasks, the time it takes to complete them, and how they depend on one another. It would show that selecting the date is a prerequisite for booking the venue, which is a prerequisite for planning the menu and hiring a caterer, and so forth. This visual representation would make it easier to plan and manage the project.
Please note this is a simplified example. In more complex projects, there might be multiple tasks that can be performed in parallel, and some tasks may depend on multiple other tasks.