Planning in MS Project: fixed work AND fixed duration

Question

I currently plan a quite complex project in MS Project. At the moment I cannot plan everything out in detail, but I think that in my head I have a good understanding of how long a task will last and how much manpower will need to go into it.

Now I would like to shift my resources back and forth to see how everything works out. For this I would like to have an overview about how loaded my resources are, but also see whether a task is understaffed. Since not all resources are on board yet, this is especially important for me to understand which qualifications I still need to hire.

MS Project only allows for fixed duration OR fixed work. Now whenever I shift a resource, I either change the amount of work or the duration of the task, depending what is fixed.

Is there a possibility to fix both at the same time? Or some other feature/method in MS Project that gives me the information that I need?

Answer 1

I don't know the answer to this but I don't think you can fix both. There is a very easy work around, however, which is to copy and paste the work planning values in a text column. And as you manipulate your resources, which will alter your work values, you can quickly copy and paste from the text column back to the work column, which will then re-calculate resources utilization, keeping the duration the same as desired and the work values as you want.

Answer 2

Your request is mathematically impossible because of how work, units, and duration are related.

work = unit * duration

For a good description of how these variables are inter-related and how changing one influences the other see my question on Simple examples of the difference between fixed-work, fixed-unit, and fixed-duration tasks in MS Project.

If you change the units (i.e. resources) either the duration or work has to change. Specifying fixed-work or fixed-duration is saying which should be held constant (and thus which should change).