Forum Discussion
Fixed duration task / Effort Driven: Why is the 3rd resource set at 50% by Project?
I just don't see why Project would assign the 3rd resource as 50%? I use Project 2019 but it's the same in Project 2013. Standard file, no edits in Kalenders or so. Work and Peak values are fine. I am fairly experienced using Project, but can't see this logic. Anyone please?
This "phenomenon" occurs when effort driven is checked (default) for a fixed duration task. The effort driven strives to keep the work content constant and you can see that in the Task Usage view as you assign each of the 3 resources consecutively.
Here's the interesting part. Instead of 3 resources, consecutively assign 4 resources at 100% to the task. As each resources is assigned you will see the Assignment Units replicate the previous resource's units while the Peak adjusts to maintain the constant work value. So for the second assignment, the assignment units is still 100% but the Peak reduces to 50%. Then when the third resource is assigned, the assignment units takes on the peak unit value from the first two assignments (i.e. 50%) and the peak now readjusts to be equal for all 3 assignments (i.e. 33%). If you assign a fourth resource, the assignment units takes on the previous peak (i.e. 33%) and the peak now readjusts to spread the original work content over 4 resources so it shows 25%.
Is this a good enough explanation for your "students"? Don't know, but it might make their heads spin a bit 🙂
I do recall there was a change to the way peak units are calculated, circa Project 2010 or Project 2013 (I think), but I don't remember the details. Whether that has anything to do with this issue, I don't know.
John
- Ed --
What is the Max. Units value for Piet? If you assign a resource to a task without entering a Units value, Microsoft Project will set the Units value to match the Max. Units value for the resource. Might that explain this mystery? Let us know and we will try to help you.- Hi Dale. Thanks for the reply.
I know what you mean, that is the odd thing here. Max units is standard 100% like the other resources. All 3 equal. I just assigned them, no manual entering values.
Thanks for your help. Could you try and replicate maybe?
For multiple resource assignments on a fixed duration, effort driven task, Project will initially equally spread the 3 assignments, so for each of the 3 assigned resources, that's 33% each. After all assignments are made then you can then edit individual assignment levels.
John
Thanks for the reply, John.
You are exactly right. Looking at the Peak column and work, it works ok. But I don't get why Project assigns the 3rd person only at 50% while I would expect another 100% also. Normal work resource, no max units edit.
I actually train people in Project and get this question sometimes and I would like to be able to explain this.
This "phenomenon" occurs when effort driven is checked (default) for a fixed duration task. The effort driven strives to keep the work content constant and you can see that in the Task Usage view as you assign each of the 3 resources consecutively.
Here's the interesting part. Instead of 3 resources, consecutively assign 4 resources at 100% to the task. As each resources is assigned you will see the Assignment Units replicate the previous resource's units while the Peak adjusts to maintain the constant work value. So for the second assignment, the assignment units is still 100% but the Peak reduces to 50%. Then when the third resource is assigned, the assignment units takes on the peak unit value from the first two assignments (i.e. 50%) and the peak now readjusts to be equal for all 3 assignments (i.e. 33%). If you assign a fourth resource, the assignment units takes on the previous peak (i.e. 33%) and the peak now readjusts to spread the original work content over 4 resources so it shows 25%.
Is this a good enough explanation for your "students"? Don't know, but it might make their heads spin a bit 🙂
I do recall there was a change to the way peak units are calculated, circa Project 2010 or Project 2013 (I think), but I don't remember the details. Whether that has anything to do with this issue, I don't know.
John
