Critical Path Pro And Cons

1. Example Of A Critical Path

Changing Task DefinitionsThe PERT system forces you to define activities as independent tasks. They must be self-contained, with a start date, a duration, a defined cost and requiring defined resources.

What is PERT?? - Advantages & Disadvantages Anonymous. The PERT network does not have a historic chain as in the case of Critical path method (CPM). Note: The PERT technique is more applicable to the projects that are newly faced, where most of the events are employed the first time or by means of a new technique. The pros and cons of. Pros and Cons. The critical path method has stood the test of time since its creation in the 1950s at Du Pont. The benefit of the critical path method is that it lays out a sequence for the steps.

In the real world, situations may change as a project progresses. While you can revise PERT to take such changes into account, preparing the initial PERT chart for a project is time-consuming and labor-intensive. Making major modifications in the chart in mid-project is often difficult. As a result, you are working with a PERT chart that no longer accurately portrays the project. Subjective Time EstimatesThe PERT chart accepts subjective project manager estimates for the duration of activities.

Its accuracy is limited by the reliability of each of the estimates of task duration. The chart remains reasonably accurate if some tasks take longer and some less time, according to a probability distribution. In real projects such a distribution may not apply, if a particular part of the work faces problems and all tasks in that area of activity are late. When the duration of these tasks increases, the tasks for which they are prerequisites are delayed, and you may have to make major revisions to the PERT chart to make it relevant again.

Near-Critical PathsOne of the key features of the PERT charts is the ability to display a critical path. The critical path is the sequence of project tasks that has the longest duration, and the total duration determines the completion date of the project. The PERT system tells you to focus on these critical tasks to ensure the project completion date remains unchanged.

The chart may contain similar task sequences whose total duration is slightly less, and the tasks are therefore not critical. If one of these tasks takes longer than estimated, the critical path may shift as the new sequence becomes the one with the longest duration. In this case you have been focusing on the wrong tasks. Changing Task RelationshipsThe PERT charts and the critical path calculations rest on tasks that have prerequisites and dependencies. In real projects, when you find that you can't meet the required prerequisites for a task, you make alternative arrangements. For example, if your power supply is going to be six months late, you might rent a generator.

Example Of A Critical Path

PERT charts are not flexible in this respect and you would have to prepare a completely revised chart. PERT charts are most effective on projects dealing with well-known processes and for which experienced personnel can accurately determine the required activities and their duration.