Compare PERT and CPM. (Oct 2003)
|
CPM |
PERT |
| 1. In CPM there is only one time given for each activity. | 1. In PERT there are three time estimates. Optimistic time, Most likely time and Pessimistic time.
From these, we find Expected time for completion of an activity (te). |
| 2. After drawing the network we find critical path. | 2. We draw the network using Expected time (te) and then we find critical path. |
| 3. There is no probability information in CPM. | 3. Probability is associated with Project completion time (Te). The probability of completing the project in that duration is 50% (0.5). |
| 4. There is no standard deviation and variance for activities. We assume that all activities will be completed in specified time. | 4. We find standard deviation and variance of critical activities and from that we find variance and standard deviation of critical path. |
| 5. As there is no probability, there is no relation with normal distribution table. | 5. We can find “z” value and from “z” value the probability of completing the project in specified time duration. |
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