Differences between PERT and CPM – Mechanical Engineering

PERT	CPM
PERT uses event oriented Network.	CPM uses activity oriented network.
Estimate of time for activities are not so accurate and definite.	Durations of activity may be estimated with a fair degree of accuracy.
It is used mostly in research and development projects, particularly projects of non-repetitive nature.	It is used extensively in construction projects.
Probabilistic model concept is used.	Deterministic concept is used.
PERT is basically a tool for planning.	CPM can control both time and cost when planning.
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, cost is the controlling factor.