Duration vs Execution time

[Jochem Davids]

I will give a small example to illustrate my problem with making a planning
in MS Project:

In example:
A task has a (planned) duration of 5 days (from Start to Finish). An
employee (resource) will effectively work on this task (planned) for 2 days
to complete it.

In MS Project there is a column for filling in the (planned) duration and
filling in the actual duration. But it seems that I cannot fill in the
planned execution time.

My question: how can I make a distinction between (planned) duration and
planned execution time of a task.

In the calculation of scheduling a task the following formula is used:
Duration = Work / Units. It seems that MS Project doesn't take the planned
execution time into account.

Does anybody know how to solve this?

 

[wayne]

Hi Jochem...I'm not sure I understand what you're trying to do and I'm fairly
new to project 2007. Assuming you're working from an effort-driven
perspective, you'd likely start by creating a task and a duration. Project
won't determine the amount of effort it will take until you assign a
resource. In your case, if you create a task that is 5d in duration, then
you assign a resource who is available 100% of the time, project will keep
the same 5d duration and make the work = 40h. If you then change your
resource allocation to 50%, project will keep the effort the same and extend
the duration to 10d.

So I guess I'm confused about what you mean when you say a rousource will
"effectively" work on the task for 2 days. There seems to be a conflict in
the expectations. Are you saying the task will take 16h of effort to execute
but that the employee will spend that effort over a 5 day period? If so,
then you should be able to set the work to 16h and allocate the employee at
40% availability, which will retain your planned 5d duration.

 

[Steve House]

As with others, I wonder what you're talking about when you use the terms
"planned execution time" and "(planned) duration." Is this the time the
resource WOULD take if he worked on it full time but because he's doing
other stuff as well it's taking him longer, say if he could give the task
his full attention it would take him 2 days but because he has other stuff
on his plate he can only work on the task in bits and pieces so it actually
takes him 5 days to do it?

 

[Jim Aksel]

You answered your own question. Duration = work/units.

If I can paint the room in 8 hours (work), and I only work on it 2 hours per
day (units=25%) then the duration = 8/25% = 32 hours (4 days).

Work - amount of effort required.
Duration - the amount of elapsed business time to complete the work.
Units - 100% is one head. 200% is two heads, 25% is 2 horus per day (one
quarter head).

That is all project understands. Work, Duration, Unitrs. Pick two -- the
third is no longer negotiable.
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Jim Aksel, MVP

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