Problem with resource scheduling

[Giannis]

Hello,
Suppose we create the following 3 tasks and assign resources A and B in the
following way:
- Task A1, Work=16h, Resources A (100%) and B (100%).
- Task A2, Work=8h, Resource A (100%), Ancestor=Task A1.
- Task B1, Work=8h, Resrouces A (100%) and B (100%).
What I would expect is:
- A is assigned 8h of Task A1 on Day 1.
- B is assigned 8h of Task A1 on Day 1.
- A is assigned 8h of Task A2 on Day 2.
- B is assigned 8h of Task B1 on Day 2.
So the project finishes in 2 days!
However what happens is the following:
- A is assigned 8h of Task A1 on Day 1 -> ok!
- B is assigned 8h of Task A1 on Day 1 -> ok!
- A is assigned 8h of Task A2 on Day 2 -> ok!
- B is assigned 4h of Task B1 on Day 2.
- A is assigned 4h of Task B1 on Day 3.
So the project takes 3 days instead. Any idea why?
Thank you!
Giannis

 

[John]

Hello,
Suppose we create the following 3 tasks and assign resources A and B in the
following way:
- Task A1, Work=16h, Resources A (100%) and B (100%).
- Task A2, Work=8h, Resource A (100%), Ancestor=Task A1.
- Task B1, Work=8h, Resrouces A (100%) and B (100%).
What I would expect is:
- A is assigned 8h of Task A1 on Day 1.
- B is assigned 8h of Task A1 on Day 1.
- A is assigned 8h of Task A2 on Day 2.
- B is assigned 8h of Task B1 on Day 2.
So the project finishes in 2 days!
However what happens is the following:
- A is assigned 8h of Task A1 on Day 1 -> ok!
- B is assigned 8h of Task A1 on Day 1 -> ok!
- A is assigned 8h of Task A2 on Day 2 -> ok!
- B is assigned 4h of Task B1 on Day 2.
- A is assigned 4h of Task B1 on Day 3.
So the project takes 3 days instead. Any idea why?
Thank you!
Giannis

Giannis,
First of all, what does "ancestor" mean? If I assume it means that task
A1 is the predecessor of Task A2 and that task B1 is concurrent with
task A1, then I suspect resource leveling has been applied. That will
give the results you indicate. However, without further clarification as
to exactly what the schedule structure is, we can't be of more help.

John
Project MVP

 

[Giannis]

John,
It's exactly as you mention: Task A1 is the predecessor of Task A2 and Task
B1 is concurrent with Task A1.
The question is WHY does the resource leveling work this way in this case?
Why can't MS Project realize that resource B can work 8h on Day 2, finishing
thus Task B1 the same day?
There is nothing else in the schedule structure of this simple project; just
these 3 tasks and the 2 resources A and B. Try it on your own on a new
project file if you want.
It's really important for me to undestand why MS Project behaves this way in
this case!

Thanks,
Giannis

 

[John]

John,
It's exactly as you mention: Task A1 is the predecessor of Task A2 and Task
B1 is concurrent with Task A1.
The question is WHY does the resource leveling work this way in this case?
Why can't MS Project realize that resource B can work 8h on Day 2, finishing
thus Task B1 the same day?
There is nothing else in the schedule structure of this simple project; just
these 3 tasks and the 2 resources A and B. Try it on your own on a new
project file if you want.
It's really important for me to undestand why MS Project behaves this way in
this case!

Thanks,
Giannis

Giannis,
Why would you expect resource B to work the full 8 hrs on task B1? You
have told Project that you are assigning TWO resources to work task B1
and B1's total work content is 8 hours. For two resources assigned
that's 4 hours apiece (unless you manually contour their work). It seems
pretty straightforward given the schedule you have set up.

I think you are expecting Project to employ a little "fuzzy" logic in
its leveling algorithm and that's just not how it works.

John
Project MVP

 

[Dave]

If A and B had different skill sets then this would be an unavoidable
consequence of your plan. When you assign those resources, Project
cannot know that they are equivalent unless you use a resource group
type of arrangement.

 

[Giannis]

Thank you for your email.
Yes, suppose that the two resources are equivalent.
How can I achieve my goal, i.e. finish the project in 2 days?
It was not possible to assign a resource group to a task.
Your help is greatly appreciated.
Thanks!

 

[Jan De Messemaeker]

Hi,

Simply said; forget it.
Project's leveling does not change assignùment unit and does not replace a
resource by an other one.
It merely gives you a feasible schedule using the assignments you entered.
Why? Because it isn't programmed like that.

Project Server has a function (substiutute resoruces) that may help you for
this (didn't test this case, though); Project Professional does not. NOT,
sorry.

Hope this helps,