Application of CPM and PERT
PERT and CPM are having applications in the following areas:
1. Manufacturing industry (Production Planning)
2. Construction Industry
3. Research and Development
4. Ship building
5. Prototyping
6. Defense projects
Difference Between PERT and CPM
| CPM |
PERT |
| It is activity oriented. | It is event oriented. |
| It is deterministic model. | It is probabilistic model. |
| Estimates project completion time. | Estimates project completion time as well as probability of completing project in that time. |
| Uses only one time estimate and assumes that the estimated time is actually the time taken by an activity. | Uses three time estimates and follows beta distribution for probabilistic time estimates. Expected time is calculated by using weighted average of three time estimates. |
| Employed to those projects where minimum overall costs are of primary importance. Better utilization of resources. | A very useful device for planning the time and resources. |
| It does not involve PERT. | It is normally use in conjunction with CPM. |
| It does not calculate standard deviation. | It calculates standard deviation. |
| It does not calculate probability of project completion. | It gives probability of project completion. |
| It is simple in nature. | It is probabilistic in nature. |
| It does not make use of the statistical devices in the determination of the time estimates. | It makes use of the statistical devices. |
| It cannot be used as a control device as it requires repetition of the entire evaluation of the project each time the changes are introduced to the network | It is used as an important control device as it assists the management in controlling a project by constant review of the delays in the activities. |
| It does not make use of dummy activities. | It makes use of dummy activities to represent the proper sequencing of the activities. |
Advantages of PERT/CPM
1. Help management to plan a project before it begins.
2. Both the techniques are very useful in scheduling and monitoring big projects of longer duration.
3. Provides an analytics approach to planning.
4. Control time and cost factors.
5. Separates the planning and scheduling functions.
6. Permits the planner to concentrate on the relationships of items of work without considering their occurrence in time.
7. Allows the planner to develop a more detailed plan, since he is concerned with how the work will be performed, not when.
8. Results in a more realistic schedule.
9. Clearly shows dependency relationships between work tasks.
10. Make control of a project very easy.
11. Simplifies maintenance of the plan and schedule.
12. Informs management of the current status of the project.
13. Focuses management’s attention on critical items of work.
14. Gives management the ability to assess consequences of anticipated changes to the plan.
15. Makes is easy to relate other functions of project control to the basic planning and scheduling function.
16. Meets contractual requirements of government, private industry and customers
Disadvantages
1. The activities, if not clearly defined and explained, can create lots of ambiguity.
2. The relationship between the activities is important to be established, otherwise chaos can be created.
3. Estimate of time is subjective and so slack time is difficult to estimate.
4. Critical path becomes the only point of emphasis and the activities on other paths may be ignores in spite of their importance.