Fixed Work Calculations when changing Actual and Remaining Duratio

[Darrel Bourne]

I am currently working with an organization that tracks schedules by
duration, but wants to evaluate Earned Value based on work estimates for each
task. Each task is created as Fixed Work, and updates are made to the plan
by entering Actual duration for the task and Remaining duration for the task.
This approach works well except under the following scenario.

When a task takes LESS time than expected, the Work value gets
re-cacluclated even though the task is Fixed Work. Lets say it is a 5 day
task with a 5 day work effort. In the process that is used to update the
schedule, if the task is done in three days, the ACTUAL DURATION will be set
to 3 days and the REMAINING DURATION to 0 days. This sets DURATION to 3
days. However, the Work changes to 3 days as well. The reason for this is
that the UNITS do not change for the Resources. It stays at 100%. This does
not fit the model of a Fixed Work Task in my opinion. Now, if I change the
DURATION field to 3 days (as opposed to the ACTUAL and REMAINING DURATION
Fields), then the Units for the Resource DOES adjust to ensure that work is a
fixed 5 days. It jsut will not do this when I adjust DURATION using ACTUAL
DURATION and REMAINING DURATION.

For tasks that take longer than plan, everything works as it should.
Updating ACTUAL DURATION to 7 days in the example above leaves Work fixed at
5 days and adjusts the Resource Units. I do not undersatnad why this works
for the one scenario and not the other.

Any assistance on this wouldbe greatly appreciated.

 

[Gérard Ducouret]

Hello,

I understand what you are expecting, but I also understand the Project's
behavior:
When you enter an Actual Duration, MSP understand "actual duration with the
planned assignment : 100%".
Then you cut off the remaining Duration : MSP can't do anything else than
decreasing the work.
I think you would have to try entering actuals in the Resource Usage view :
insert the Actual Work row.

Gérard Ducouret

 

[Darrel Bourne]

I 'understand' the behavior to a point. I agree what you are saying is what
Porject is doing, and perhaps that is by design. However, by setting the
task as Fixed Work, I am asking the application to change the Units. not the
work

Also please note that when the tasks lengthens, as in my example, the work
value does NOT change and the resoruce Units are changed from 100% to a
lesser amount to keep the formula accurate. So this behvavior only occurs
when the task is shortened in duration.

It just does not seem consistant.

 

[Gérard Ducouret]

I agree with you...

Gérard Ducouret

I 'understand' the behavior to a point. I agree what you are saying is
what
Porject is doing, and perhaps that is by design. However, by setting the
task as Fixed Work, I am asking the application to change the Units. not
the
work

Also please note that when the tasks lengthens, as in my example, the work
value does NOT change and the resoruce Units are changed from 100% to a
lesser amount to keep the formula accurate. So this behvavior only occurs
when the task is shortened in duration.

It just does not seem consistant.

 

[Steve House]

How could you possibly do 5 days of work in 3 days of time? To make it
clearer, convert everything to hours. 5 days of work is 40 man-hours,
assuming a standard 8 hour workday. 3 days of duration is 24 hours of time.
How is it possible for any human to achieve 40 hours of work during 24 hours
of time? Now he might "compress" the task by doing overtime, doing 24
man-hours straight time + 16 man-hours overtime - that gives you 40 hours of
work over 24 hours of duration since straight time is the only thing that
counts for duration but that's a diferent issue altogether and if that's
what happened you have to enter it into the usage views that way. He might
screw around and output LESS than an hour's worth of work for each hour he
puts in but absent overtime work it's physically impossible for him to
generate more than an hour of work during an hour of duration time.

Fixed Work (or duration or units) does not mean that those values never
change under any circumstances. They apply in the situation where when you
edit one of the terms of the equation W=D*U, which term should be held
constant so that the third term is recalculated. But you're not editing the
assignments here, you're updating estimates with actuals, effectively
redoing the assignment, and that's a whole different kettle of fish
altogether.