Elapsed duration & Fixed duration (98)

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I am trying to get my head round elapsed duration tasks. I understand that with an elapsed duration task it is scheduled irrespective of the work calendar, so e.g. a 5 day elapsed duration task would constitute 120 hours work (5 x 24) and could be scheduled over a non-working weekend.

I have read that an elapsed duration task is automatically defined as fixed duration. When I add / remove resources, the task duration and the task work remain unaltered. It does therefore seem to act like a Fixed Duration, Effort Driven task. But when I look at the Task Information it is shown as Fixed Units, Effort Driven

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What are you using elapsed duration tasks for? Elapsed time is a designation generally used for tasks that can span across non-working days. By inference this would mean that resources would not probably be assigned to these tasks. The textbook example of when elapsed time is used is when you have a construction task like allowing concrete to cure. This task will happen in its time frame regardless of if there are resources available or not .

If you want to schedule a particular resource to work on non-working days defined in the Project base calendar you would go to the calendar for the resource you want to assign to the task and make the particular non working days working days. This would allow this resource to work on what would otherwise be a non working day.

I have had good results in Project by not using the effort driven check box to control resource assignments. Project uses the resource scheduling formula Work = Duration * Units so for example if you assign resource A to a four day duration task the result would be Resource A is 1 full time unit * 4days * 8 hours per day = 32 hours of work. Project also uses Effort Driven scheduling by default. Another words if you have a 4 day task with Resource A assigned for 32 hours and you then also assign Resourse B to the task Resource A and Resource B will work full time on what becomes a 2 day task for 16 hours each for a total of 32 hours.

To maintain the integrity of this formula each time you edit or change one of the three variables in the scheduling formula Project will recalculate one of the other two remaining variables.

By default Project uses Fixed Unit Task type.

To control which variable project will recalculate you can set a task type of Fixed Duration, Fixed Units or Fixed Work. Setting a task type means Project won’t recalculate the value for that particular variable when assignments are edited, it does not mean the value cannot be changed. During the implementation of the project any of the three values can be edited regardless of the task type.

Work and Duration are separate fields in Project they are not the same thing. Duration is the chronological time between the start and finish of a task, Work is the work effort or number of hours needed to accomplish the task.

You might have a task of 4 days duration with 2 full time resources assigned for a total of 32 hours work, or you might have a 4 day duration task with one resource assigned for only 8 hours work within the time frame. Both of these scenarios could easily be created by using a Fixed duration task type.

I have found the split view of Gantt chart in the top of the screen and the task form in the bottom of the screen to be a good interface for assigning resources. This view displays all of the information pertinent to assigning resources, and allows you to make appropriate changes.

Good Luck,
Carla

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Thank you Clara.

Can you confirm my understanding of your reply?

Am I understanding correctly that I should only be using elapsed duration when I am not going to assign resources and that therefore it is irrelevant that the task

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Hi Alice,

This strategy has worked well for me, and you have understood exactly what I posted. I have found there are many options to do things Project, but it is not necessary to use all of them. The bottom line on resource assignments is do you have the hours, duration and units assigned that you invisioned.

Carla

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Thanks Carla – it’sclear now for me.

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Thanks Carla – it’sclear now for me.

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Hi Alice,

This strategy has worked well for me, and you have understood exactly what I posted. I have found there are many options to do things Project, but it is not necessary to use all of them. The bottom line on resource assignments is do you have the hours, duration and units assigned that you invisioned.

Carla

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Thank you Clara.

Can you confirm my understanding of your reply?

Am I understanding correctly that I should only be using elapsed duration when I am not going to assign resources and that therefore it is irrelevant that the task

Reply | Quote

What are you using elapsed duration tasks for? Elapsed time is a designation generally used for tasks that can span across non-working days. By inference this would mean that resources would not probably be assigned to these tasks. The textbook example of when elapsed time is used is when you have a construction task like allowing concrete to cure. This task will happen in its time frame regardless of if there are resources available or not .

If you want to schedule a particular resource to work on non-working days defined in the Project base calendar you would go to the calendar for the resource you want to assign to the task and make the particular non working days working days. This would allow this resource to work on what would otherwise be a non working day.

I have had good results in Project by not using the effort driven check box to control resource assignments. Project uses the resource scheduling formula Work = Duration * Units so for example if you assign resource A to a four day duration task the result would be Resource A is 1 full time unit * 4days * 8 hours per day = 32 hours of work. Project also uses Effort Driven scheduling by default. Another words if you have a 4 day task with Resource A assigned for 32 hours and you then also assign Resourse B to the task Resource A and Resource B will work full time on what becomes a 2 day task for 16 hours each for a total of 32 hours.

To maintain the integrity of this formula each time you edit or change one of the three variables in the scheduling formula Project will recalculate one of the other two remaining variables.

By default Project uses Fixed Unit Task type.

To control which variable project will recalculate you can set a task type of Fixed Duration, Fixed Units or Fixed Work. Setting a task type means Project won’t recalculate the value for that particular variable when assignments are edited, it does not mean the value cannot be changed. During the implementation of the project any of the three values can be edited regardless of the task type.

Work and Duration are separate fields in Project they are not the same thing. Duration is the chronological time between the start and finish of a task, Work is the work effort or number of hours needed to accomplish the task.

You might have a task of 4 days duration with 2 full time resources assigned for a total of 32 hours work, or you might have a 4 day duration task with one resource assigned for only 8 hours work within the time frame. Both of these scenarios could easily be created by using a Fixed duration task type.

I have found the split view of Gantt chart in the top of the screen and the task form in the bottom of the screen to be a good interface for assigning resources. This view displays all of the information pertinent to assigning resources, and allows you to make appropriate changes.

Good Luck,
Carla

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