What is the Difference Between CPM and PERT?

The main differences between Critical Path Method (CPM) and Project Evaluation and Review Technique (PERT) are as follows:

1. Uncertainty: PERT is used to manage uncertain activities in a project, where the time required is not known, and is appropriate for projects with non-repetitive nature, such as research and development projects. In contrast, CPM is used to manage well-defined activities with predictable time requirements and is suitable for projects with repetitive nature, such as construction projects.
2. Technique Type: PERT is an event-oriented technique that focuses on time management and control, while CPM is an activity-oriented technique that focuses on both time and cost management.
3. Probabilistic vs. Deterministic: PERT uses a probabilistic model, with three time estimates (optimistic, most likely, and pessimistic) for each activity. CPM, on the other hand, uses a deterministic model with a single time estimate for each activity.
4. Critical Path: PERT does not differentiate between critical and non-critical activities, while CPM separates critical and non-critical activities. The critical path in CPM is the longest path in the project, providing the minimum time required for project completion.
5. Focus: PERT majorly focuses on time management, aiming to meet time targets or estimate percent completion. CPM focuses on the time-cost trade-off, prioritizing minimizing costs.

In summary, PERT is more suitable for projects with uncertain activities and non-repetitive nature, while CPM is better for projects with well-defined activities and repetitive nature. Both techniques help project managers plan, schedule, and control tasks, but they differ in their approach to uncertainty, time management, and cost control.

Comparative Table: CPM vs PERT

The main differences between CPM and PERT are their focus, project orientation, and model type. Here is a table summarizing the differences:

PERT (Project Evaluation and Review Technique) is a project management technique used to manage uncertain activities of a project, focusing on minimizing the time required for completion. It is an event-oriented technique and uses a probabilistic model. PERT is best suited for non-repetitive jobs with unpredictable activities.

CPM (Critical Path Method) is a project management technique used to manage certain activities of a project, focusing on time-cost trade-offs. It is an activity-oriented technique and uses a deterministic model. CPM is more suitable for repetitive jobs with predictable activities and emphasizes cost-cutting.