Pessimistic duration task field

Data Type     Duration

Entry Type     Calculated or entered

Description     The Pessimistic Duration field contains the worst-case possibility for the total span of active working time expected for a task, that is, the amount of time from the pessimistic start to the pessimistic finish of a task. You can enter the pessimistic duration as part of a PERT analysis calculation, which takes a weighted average of expected, pessimistic, and optimistic dates and durations, or you can have Microsoft Office Project calculate it for you. This field is available only in the PA_Pessimistic Case table or the PA_Pessimistic Gantt view. 

How Calculated     When you first create a task, the Pessimistic Duration field contains "NA." When you enter pessimistic start and finish dates, and then click Calculate PERT  on the PERT Analysis toolbar, a probable worst-case duration is calculated and placed in the Duration field.

Best Uses     Use the Pessimistic Duration field in the PA_Pessimistic Case table or the PA_Pessimistic Gantt view to estimate the probabilities of task dates. By default, the PERT analysis calculation gives heaviest weight (4) to the expected information, and the lightest weight (1 each) to the pessimistic and optimistic information.

Example     You have several critical tasks for which you want to see the best-case, worst-case, and expected durations. You enter the expected start and finish dates for these tasks, as well as their optimistic and pessimistic start and finish dates, and then run the PERT analysis calculation.

Remarks     By changing the weight that Project attributes to each of the three estimated durations, you can tailor the probable estimate to be more accurate. To change the weight, click PERT Weights   on the PERT Analysis toolbar, and then alter the default settings.

The Pessimistic Duration field uses the Duration3 custom duration field.