Project evaluation and review technique

Another way to express the duration of the project is shown in the project evaluation and review technique (pert) diagram. Developed during the 1950s by the US Department of Defence, it helps identify the critical path and establish the earliest and latest start and finish times, duration and floats. The product flow diagram for the example above would look like Figure 7.13.

The circles represent milestones and 10, 20, 30 and 40 are equivalent to products 1, 2, 3 and 4. They are numbered in tens so that additional milestones may be added if necessary. In this example, 50 represents the end of the project. The numbers in between are the duration of activities.

There are some important differences between this expression, the product flow diagram and the Gantt chart, as well as some limitations. For instance, the pert diagram shows five milestones where the product flow diagram showed four. This is because the project evaluation and review technique requires each milestone circle to consume no time and require no resources. Therefore, the duration associated with each milestone is shown on the line that succeeds it. Thus the duration between milestone 40 and the end of the project, milestone 50, is four days. From a product-based perspective, milestone 50 might be questioned. What are its success criteria? Are they any different from those of milestone 40? If they are, might extra time be needed to achieve them?

This is not a technique to be used in addition to the approach described during this chapter, but as an alternative. Although it makes reference to milestones that may be considered "products", the emphasis on the quality definition of the products is far less. Furthermore, pert is intentionally a means of representing a time schedule. It is rarely used to develop budgets.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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