PERT and CPM: Similarities, Differences

Program Evaluation and Review Technique (PERT) and  Critical path Method (CPM) are the most commonly used methods for project management. There are some similarities and differences between PERT and CPM. PERT can be applied to any field requiring planned, controlled and integrated work efforts to accomplish defined objectives. On the other hand, CPM is the method of planning consisting of several well-defined and clearly recognizable activities.

Comparison between PERT and CPM:

S.no	PERT	CPM
1	PERT uses an event-oriented Network.	CPM uses activity oriented network.
2	In PERT estimate with a fair degree of accuracy.	In CPM, durations are estimated with a reasonable degree of accuracy.
3	PERT is commonly used in research and development projects, particularly projects of non-repetitive nature.	CPM is used extensively in construction projects.
4	In PERT, the probabilistic model concept is used.	In CPM, the deterministic concept is used.
5	PERT is basically a tool for planning.	CPM can control both time and cost while planning.
6	In PERT, it is assumed that cost varies directly with time. Attention is therefore given to minimize the time so that minimum cost results. Thus in PERT, time is the controlling factor.	In CPM, cost optimization is given prime importance. The time for the completion of the project depends upon cost optimization. The cost is not directly proportioned to time. Thus, the cost is a controlling factor.

While both Program Evaluation and Review Technique (PERT) and  Critical path Method (CPM) are valuable tools in project management, they serve different needs and contexts. PERT is beneficial for uncertain projects, while CPM is ideal for projects with clearly defined timelines and costs.