Hi,

You can find a lot of examples when you can see that it is possible to assign Resource to Tasks with 0% Units. In this post I will show you how can you do it, and what would happen if you do it. Of course, I will use MS PROJECT 2016!

First I will create very simple Project with 2 Tasks:

and two Resources – John and Mary:

As you can see, for this example, John has 0% Max Units by default, and Mary has 100%.

Now I will assign John To Task 1:

and I will get (I will show Task Usage View):

As you can see, John is over allocated, because by default (since I did not enter Units in the Units field shown in a picture above) Units are 100%. So, in Resource sheet his default Max. Units field is 0%, but he is allocated (or assigned) to Task 1 with 100%, and now he is Over allocated, and he is suppose to work 8 hours per day, e.g. 40 hours for the Whole Task.

Now I will assign Mary to the Task 2 with 0%:

and I will get (I will show Task Usage View):

As you can see, Mary will work zero hours (because she is assigned with zero %), and Task duration is now 0 days, so it is Milestone now.

OK! Now you know combinations with 0% units assigned. But, the most important question is WHY? Why will someone assign Resource to the Task with 0% Units, or why will someone have Resource in Resource sheet with default Max units = 0%?

If you have Resource with 0% Max units in Resource sheet it means that you have Resource which is unavailable all the time for all Project activities, and every assignment with Units > 0% will result in over allocation. This can be use in rare situation when you know that you, actually do not have Resource available, but in urgent case, where you have no other option you will use it so these Resource will work over time, e.g. it will be overrated.

On the other hand, if you assign Resource to the Task, and you put 0% in Units, it means that this Resource will do no work on the Task, e.g. it will not spend a single second on it. So, the right question will be: “Why should someone assign this Resource to the Tasks?”. The answer is (from my point of view): There is no reason for that, except if you have some administrative procedure, let’s say that you want to assign Mary, as a Project Manager responsible for this Task, but she will actually do nothing on it.

Hope this helps.

Regards.