PERT Chart

PERT Chart

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The Program Evaluation Review Technique (PERT) chart is a project management tool used to schedule, organize, and analyze the tasks involved in a complex project. It is a graphical representation of the project’s timeline, critical path, and interdependencies between tasks. PERT charts are widely used in industries such as construction, engineering, software development, and research, where projects have multiple activities that need to be coordinated effectively.

Key Elements of a PERT Chart:

  1. Nodes: Nodes represent individual tasks or activities in the project. Each node is represented by a circle or a box and is labeled with the name of the task and its unique identifier.
  2. Arrows: Arrows, also known as arrows or lines, connect the nodes and indicate the flow and dependencies between tasks. The direction of the arrow shows the sequence in which tasks should be performed.
  3. Time Estimates: Each task is associated with time estimates, including optimistic (O), most likely (M), and pessimistic (P) estimates. These estimates are used to calculate the expected duration of each task.
  4. Critical Path: The critical path is the longest sequence of dependent tasks that determines the minimum time required to complete the project. Any delay in tasks on the critical path will directly impact the overall project timeline.
  5. Event Points: Event points represent milestones or significant points in the project, such as project start, project completion, or key deliverables.

How PERT Chart Works:

  1. Identify Tasks: The first step in creating a PERT chart is to identify all the tasks or activities required to complete the project. Each task should have a clear start and end point.
  2. Sequence of Tasks: Determine the order in which tasks need to be performed and establish the dependencies between them. This will help in creating the arrows between the nodes.
  3. Time Estimates: Assign time estimates for each task, including optimistic, most likely, and pessimistic estimates. These estimates are used to calculate the expected duration for each task.
  4. Construct the PERT Chart: Using the information from the previous steps, construct the PERT chart by drawing nodes for each task and connecting them with arrows to represent the sequence and dependencies.
  5. Calculate Expected Duration: Calculate the expected duration for each task based on the time estimates and the PERT formula: Expected Duration (TE) = (O + 4M + P) / 6.
  6. Identify Critical Path: Determine the critical path by identifying the longest sequence of tasks with no slack or float. Any delay in tasks on the critical path will extend the project’s overall duration.

Benefits of PERT Chart:

  1. Visualization: PERT charts provide a visual representation of the project, making it easier to understand the project’s flow and dependencies.
  2. Time Management: PERT charts help in identifying critical tasks and their expected duration, enabling better time management and scheduling.
  3. Resource Allocation: PERT charts assist in identifying tasks that can be performed concurrently and allocate resources accordingly.
  4. Risk Management: By identifying critical tasks and potential delays, PERT charts help in managing project risks effectively.


The Program Evaluation Review Technique (PERT) chart is a powerful project management tool that provides a visual representation of project tasks, their dependencies, and critical path. It helps project managers in effective planning, scheduling, and resource allocation, ultimately leading to the successful and timely completion of complex projects. PERT charts are widely used in various industries to streamline project workflows and ensure project success.

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