Understanding Project Scheduling: PERT/CPM Network Diagram Simplified

Project scheduling helps organize tasks and ensures that a project is completed on time. Two popular methods used for scheduling are PERT (Program Evaluation and Review Technique) and CPM (Critical Path Method). Both methods involve creating a Network Diagram, which visually shows the sequence of tasks, their duration, and dependencies.

What is a Network Diagram?

A Network Diagram is a flowchart that displays all the tasks (called activities) in a project and the order in which they need to be completed. It helps identify which tasks depend on others and how long the project will take. In both PERT and CPM, the diagram shows the critical tasks that cannot be delayed without delaying the entire project.

Key Elements of PERT/CPM Network Diagram

• Nodes: Represent tasks or activities in the project.
• Arrows: Indicate the sequence or order in which tasks must be completed (dependencies).
• Critical Path: The longest path in the network, showing the sequence of tasks that must be completed on time to avoid delaying the project.

Differences Between PERT and CPM

• PERT: Focuses on estimating time when there’s uncertainty by using optimistic, pessimistic, and most likely time estimates.
• CPM: Focuses on fixed task durations and is used when tasks have definite deadlines.

How to Create a PERT/CPM Network Diagram?

1. List the Project Tasks

Write down all the tasks (activities) that need to be completed for the project.

2. Determine Task Dependencies

Identify which tasks depend on others being completed before they can start.

3. Estimate Task Duration

For each task, estimate how long it will take to complete. If using PERT, you estimate three durations: optimistic, pessimistic, and most likely.

4. Draw the Network Diagram

• Represent each task as a node (a circle or box).
• Use arrows to connect the tasks and show their dependencies.
• Mark the estimated duration on each task.

5. Identify the Critical Path

The Critical Path is the longest sequence of tasks in the project. Any delay in tasks on the critical path will delay the entire project.

Example: Creating a Network Diagram for Course Development

Imagine your IT Training Center is developing a new 5-day Cybersecurity course. Here’s how you can apply PERT/CPM:

Step 1: List of Tasks

• Task A: Course Outline
• Task B: Content Creation
• Task C: Video Recording
• Task D: Editing Videos
• Task E: Uploading Content to the Platform
• Task F: Marketing the Course

Step 2: Task Dependencies

• Task B (Content Creation) depends on Task A (Course Outline).
• Task C (Video Recording) depends on Task B.
• Task D (Editing) depends on Task C.
• Task E (Uploading) depends on Task D.
• Task F (Marketing) can start after Task B.

Step 3: Estimate Task Duration (in days)

• Task A: 2 days
• Task B: 5 days
• Task C: 3 days
• Task D: 2 days
• Task E: 1 day
• Task F: 4 days

Step 4: Draw the Network Diagram

• Task A → Task B → Task C → Task D → Task E
• Task B → Task F (independent of the other path)

Step 5: Identify the Critical Path

The critical path is A → B → C → D → E because this path takes the longest (13 days in total). Any delay in these tasks will delay the entire project.

Task F (Marketing) can happen in parallel and doesn’t affect the course development directly, so it’s not on the critical path.

Why is the Network Diagram Useful?

• Clear Visual: It shows the order of tasks and their durations at a glance.
• Identifies Critical Path: Helps focus on tasks that cannot be delayed.
• Improves Time Management: Enables better planning and scheduling of resources to ensure timely project completion.

Conclusion

Using a Network Diagram with PERT/CPM helps plan and manage your project efficiently. By understanding the critical path, you can identify which tasks are crucial for meeting your deadlines, ensuring successful project delivery for your training center’s courses.