today I will show you relationship between Duration and Effort in Project for the Web.
I will first create simple Project:
Now I will assign me, and Ellen to Task with Resources:
and I will get:
As you can see, effort is 80 hours! And this is because me and Ellen are going to work 5 days, 8 hours per day, e.g. 5 days * 8 hours per day each = 40 per person, in Total = 80 hours! Now I will change effort to 32 hours:
and when I hit Enter, I will get:
The Duration is 2 days, because 32 hours (effort) is divided between me and Ellen, so each will work 32 hours / 2 persons = 16 hours, and because we are going to work 8 hours per day, duration is 16 hours / 8 hours per day = 2 days!
So, to conclude this part, if you have a Task with Resources assigned if you change duration , effort will be calculated and vice versa.
Now, I’m going to put 32 hours in effort field for Task without Resources, an when I hit Enter key, I will get:
As you can see, Duration is the same = 5 Days! I will now change the Duration to 100 Days, and I will get:
As you can see, Effort remain the same (e.g. 32 hours).
To conclude, if the Task has assigned resources, Effort and Duration are connected according to formula: Effort = SUM(8 hours per day * Duration for all Resources). On the other hand, if Task has no resources assigned, Effort and Duration are not connected, and when you put some value into Duration, Effort will be unchanged and vice versa.