MS Project not re-calulating units when changing task duration

Copper Contributor

Given I have a task set to Type="Fixed Work" and Task Mode = "Auto Schedule" and I have set Work and Duration to fixed numbers, when I increase duration and select "Decrease the hours resources work per day (units) but keep the same amount of work" in the dialogue box, I would expect the units for the assigned resource to decrease. However, nothing happens!


On the other hand, if I change the work and select the corresponding menu option, the units for the resourse is changed,


Is this an error in the SW?

5 Replies
Why do you say the assignment units doesn't change. Let me guess, you are looking at the Assignment Units field and that will indeed show no change. What you should be looking at is the Peak field. You will see that it DOES change. This apparent anomaly is by design and is due to a change the Project developers made with the release of Project 2010. This is a quote (I don't know the specific link) from Microsoft.
"In Project 2007, and previous versions, when this value differs from 100% we show it next to the resource name in the Gantt chart. For Project 2010 we’ve made some changes to the way that the Assignment Units field is calculated. Primarily, these changes were made in response to customer feedback about the way calculations were impacted when resources entered overtime work. For this release we’ve clarified the definition of the Peak field and the Assignment Units field which previously had some functional overlap but now fill more defined, separate, roles. As a result of these changes the Assignment Units field is no longer automatically modified to be greater or less than default value of 100%; as a consequence the field does not show up in the Gantt chart as often as it used to."

Hope this helps.

@John-project It did indeed clear up some misunderstanding from my side. I think the allocation next to the resource name can be a little confusing though. Do you know if there is a way to tell Project not to show it?

Hello It is certainly confusing the value that is displayed in the task view. In the Task Usage or Resource Usage view, automatic changes to the resource's Assignment Units are displayed

@chrjensen1735 I assume you are referring to the resource name next to the Gantt bar. There is no option setting to turn off the assignment value next to the name but you can do it with a custom field formula. Then edit the Bar Styles to show the custom field instead of the Resource Names field. Here's what it might look like.


Of course the formula gets more complicated if more than one resource is assigned. In that case I'd use VBA.







The following example shows the distribution of resources in time, through the Timephased included in the Task Usage View and in the Resource Usage View. Probably the only views that allow to show the result of the units recalculation, when the duration of a Fixed Work Type task is changed.




The example shows first the case of a Task 1, with a Duration of 10 days, a Work of 80 hours, and a single Resource A (1 Unit).


The following image shows the result of the manual reduction of the Durations of the tasks in half (5 days), so that by keeping the work constant (80 hours), Ms Project doubles the number of resources assigned to the task (2 Units), according to the formula:


Work = Duration x Resource Units



Note.- To show the Units field (Peak Units), in the timephased: Click with the right mouse button on the timephased, select Detail Styles..., and move Peak Units field from the list on the left to the right area of Show these fields, and OK.