CPM and PERT

Critical path method (CPM)

  

Network analysis technique used in complex project plans with a large number of activities. CPM diagrams (1) all activities, (2) time required for their completion, (3) and how each activity is related to the previous and next activity. A sequence of activities is called a 'path,' and the longest-path in the diagram is the critical path. It is 'critical' because all activities on it must be completed in the designated time, otherwise the whole project will be delayed. Also called critical path analysis or critical path methodology.

PERT(Program (or Project) Evaluation and Review Technique)

The Program (or Project) Evaluation and Review Technique, commonly abbreviated PERT, is a statistical tool, used in project management, that is designed to analyze and represent the tasks involved in completing a given project. First developed by the United States Navy in the 1950s, it is commonly used in conjunction with the critical path method or CPM.

The Major Differences and Similarities between PERT and CPM

PERT (Program Evaluation and Review Technique) | CPM (Critical Path Method)
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1)PERT is a probabilistic tool used with three 1)CPM is a deterministic tool, with only single
Estimating the duration for completion of estimate of duration Activities.
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2) This tool is basically a tool for planning 2)CPM also allows and explicit estimate of
and control of time. costs in addition to time, therefore CPM can 
control both time and cost.
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3)PERT is more suitable for R&D related 3)CPM is best suited for routine and those
projects where the project is performed for projects where time and cost estimates can
the first time and the estimate of duration be accurately calculated.
are uncertain.
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4) The probability factor i major in PERT 4)The deterministic factor is more so values or
so outcomes may not be exact. outcomes are generally accurate and
realistic.