Article ID: 87301 - View products that this article applies to.
This article was previously published under Q87301
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Tasks with elapsed durations, rather than working durations, may introduce slack into a project because these tasks can extend into nonworking portions of the project calendar.
Setting an elapsed duration on a task (for example, "1ed" as opposed to "1d") fixes the duration of the task in an absolute sense. An elapsed duration allows Project to extend the task into nonworking portions of the project calendar. A "4eh" (4 elapsed hours) task that began at 2pm, for example, would finish at 6pm without regard to the project calendar. This may result an unexpected amount of slack for some tasks.
NOTE: For this example, use the Standard project calendar.
Because task 1 has a working duration of 8h, no portion of that task can be scheduled between 7/24 5pm (Friday) and 7/27 8am (Monday); hence, it has no slack.
However, task 2 has an elapsed duration of 9eh, and so could be scheduled to start as late as 7/28 11pm (Sunday) and still not delay task 3. The Total Slack is the difference between 8am Friday and 11pm Sunday, 2.63ed (63h).
Note that elapsed duration tasks are scheduled to start just as any other task; that is, they are scheduled to start only during calendar working hours. The elapsed duration implies only that the task can extend into nonworking hours once having started. For task 2 to start between 5pm Friday and 8am Monday, it would have to be forced with either a Constraint or an Actual Start/Finish date.
Article ID: 87301 - Last Review: February 27, 2014 - Revision: 5.0