30/05/2024
Key Differences Between PERT and CPM
The most important differences between PERT and CPM are provided below:
1. PERT is a project management technique, whereby planning, scheduling, organising, coordinating, and controlling uncertain activities are done. CPM is a statistical technique of project management in which planning, scheduling, organising, coordination, and control of well-defined activities take place.
2. PERT is a technique of planning and control of time. Unlike CPM, which is a method to control costs and time.
3. While PERT has evolved as a research and development project, CPM evolved as a construction project.
4. PERT is set according to events while CPM is aligned towards activities.
5. A deterministic model is used in CPM. Conversely, PERT uses a probabilistic model.
6. There are three times estimates in PERT, i.e. optimistic time (to), most likely time โข, and pessimistic time (tp). On the other hand, there is only one estimate in CPM.
7. PERT technique is best suited for a high-precision time estimate, whereas CPM is appropriate for a reasonable time estimate.
8. PERT deals with unpredictable activities, but CPM deals with predictable activities.
9. PERT is used where the nature of the job is non-repetitive. In contrast, CPM involves jobs of a repetitive nature.
10. There is a demarcation between critical and non-critical activities in CPM, which is not in the case of PERT.
11. PERT is best for research and development projects, but CPM is for non-research projects like construction projects.
12. Crashing is a compression technique applied to CPM, to shorten the project duration, along with the least additional cost. The crashing concept is not applicable to PERT.