# Project Professional - Calculate task duration with fixed work duration and variable resources

Copper Contributor

# Project Professional - Calculate task duration with fixed work duration and variable resources

Hello dear community,

I have the following problem: I want to find out how long an operation takes when I have multiple resources, each with different workloads on the operations.

Example: I have 2 people, person A and person B, and multiple operations.

If I assign operation 1 to person A and plan the resource with 100%, I get 5 days with fixed work and activity controlled operation with 40h work.

If I assign operation 1 to person A and reduce the utilization of the resource to 50% at constant work (40h), the duration is extended to 10 days.

So far so good.

Let's go one step further - same operation, activity controlled, 40h work. Premise: Person A and person B can do the same work.

Operation 1 is assigned to person A and person B. Both work with 100%. The operation has 40h work --> The duration is calculated with 2,5 days.

Operation 1 is processed by person A and person B, both work with 50%, the operation still needs 40h work --> The duration is calculated with 5 days.

So far all is well.

Operation 1 is assigned to person A at 100% and to person B at 50%, still 40h work - and the operation is still displayed with 5 days. I would have expected 3.33 days.

I.e. I assume that MS Project expects both resources to be able to work on it at the same time when assigning resources?

Is there any way to map individual resources to their capacities like this?

Combining both people into one group and simply specifying 150% is unfortunately not an option, as unlike the example, the project is far more complex and in some cases 4 or 5 people may be working on a task, each person with a different kappa, which can always change.

Thank you very much!

Kind regards

Translated with www.DeepL.com/Translator (free version)

3 Replies

# Re: Project Professional - Calculate task duration with fixed work duration and variable resources

This is what I get when I input your last scenario.

I do find that sometimes when running successive scenarios as you outlined, Project can get "confused". Even though you may delete data inputs from a previous scenario, internally that information may still exist such that it interacts with the new scenario. I've experienced that phenomenon before and I saw it again as I successively worked through each of your scenarios.

So....for your last scenario, 40h fixed work, resource A at 100% and resource B at 50%, the duration does indeed show as 3.33 days, assuming the Standard calendar.

John

# Re: Project Professional - Calculate task duration with fixed work duration and variable resources

Hello dear John,

thank you very much for your answer! I tried the whole thing now also around that I entered the last scenario directly. This has also worked for me, as it did for you.
However, as you say, Project is "confused" if there were other scenarios on the task before.

Unfortunately I have the problem that my projects can be very "dynamic", i.e. it can happen that resources can be withdrawn at short notice, but can be added elsewhere at short notice for each and every task.

Therefore I need a solution that is not "confused" by previous scenarios of resource distribution. Is this possibly a setting thing? Alternatively, does the whole project plan need to be "updated" somehow?

Thanks a lot!

Best regards

# Re: Project Professional - Calculate task duration with fixed work duration and variable resources

The "confusion" comes from testing consecutive scenarios and using Undo after each. This won't occur during normal updating of the plan wherein the project is updated, saved and then again updated during the next update cycle. So there is no option "setting" you need to change.

John