# Use a PERT analysis to estimate task durations

You can perform a Program, Evaluation, and Review Technique (PERT) analysis to estimate a task's (task: An activity that has a beginning and an end. Project plans are made up of tasks.) duration.

1. On the View menu, point to Toolbars, and then click PERT Analysis.
2. On the PERT Analysis toolbar, click PERT Entry Sheet .
3. For each task, enter the optimistic, expected, and pessimistic durations in the Optimistic Dur., Expected Dur., and Pessimistic Dur. fields, respectively.

If a task's duration is not expected to vary, enter the expected duration in all three fields.

1. Click Calculate PERT to calculate the estimated durations.

Microsoft Office Project 2003 estimates a single project duration based on a weighted average of the three duration values for each task.

1. To view the optimistic, expected, and pessimistic durations, on the PERT Analysis toolbar, click Optimistic Gantt , Expected Gantt , or Pessimistic Gantt .
2. To view the end dates of the three resulting schedules, on the Tools menu, click Options.
3. Click the View tab, and then select the Show project summary task box.

1. On the View menu, point to Toolbars, and then click PERT Analysis.
2. On the PERT Analysis toolbar, click Set PERT weights .
3. Change the number in at least two of the following fields—Optimistic., Expected., and Pessimistic.—so that the sum of all three numbers equals 6.
4. On the PERT Analysis toolbar, click PERT Entry Sheet .
5. For each task, enter the optimistic, expected, and pessimistic durations in the Optimistic Dur., Expected Dur., and Pessimistic Dur. fields.

If there is a task duration that you do not want to have calculated, enter the same duration in all three fields.

1. Click Calculate PERT .

Project estimates a single project duration based on a weighted average of the three duration values for each task.

1. To view the optimistic, expected, and pessimistic durations, on the PERT Analysis toolbar, click Optimistic Gantt , Expected Gantt , or Pessimistic Gantt .
2. To view the end dates of the three resulting schedules, on the Tools menu, click Options.
3. Click the View tab, and then select the Show Project summary task box.

Note   The Network Diagram view was formerly called the PERT Chart in earlier versions of Project. If you want to review tasks as a flowchart, instead of calculating best and worst case scenarios, use the Network Diagram view.

Applies to:
Project 2003