Fixed Work Doesn't Stay Fixed with Multiple, Uneven Assignments

[Brian Lukanic]

* Project 2003
* Task type: Fixed Work (and effort driven, as it has to be)
* Multiple resource assignments. Each resource's unit value is different.
* I have values entered for all elements (duration, work, units)

The problem:
* If I increase duration on the task, then the unit values decrease and a
Smart Tag is thrown. This works just as I would expect it to (I.E. it does
not change the fixed value.)
* But if I decrease duration on the task, the work decreases and keeps the
unit values fixed. It is almost as if Project is treating the task as Fixed
Units. But my task type is Fixed Work!!

Question:
* Why does Project fail to increase unit values when I decrease duration on
a Fixed Work task? Is it because Project is unable to make the call as to how
to re-rate the % values of each resource?
* why does Project not even give me a Smart Tag to help it decide?

 

[JulieS]

Hi Brian,

Well, I have to say, that what you report is not how Project *should*
work. On a fixed work task type if you decrease task duration, Project
will increase assignment units for the "driver resource."

You don't give the details so I'll throw an example out there.

Task with 200 hours of work in total.
Bob - 100% assignment units - 110 hours of work
Sue - 100% assignment units - 20 hours of work
Mary - 100% assignment units - 70 hours of work

Task duration: 13.75 days
Fixed Work task type.

If I drop the duration of the task from 13.75 days to 10 days:
Bob - 138% assignment units - 110 hours of work
Sue - 100% assignment units - 20 hours of work
Mary - 100% assignment units - 70 hours of work

Total amount of work is still 200 hours. Bob's assignment units
increased because Bob's 110 hours were being finished last on the task.
Sue and Mary because they were working fewer hours and at 100%
assignment units were finishing the work on the task several days
earlier.

I'm not sure what is at the root cause of what you report. Have you
tried splitting the screen (Window > Split) to show the task form at the
bottom? Is the task in question truly Fixed Work? Let us know more
details and we'll see if we can reproduce what you report.

Smart tags only show if you change duration in the duration field. If I
show the Task Form at the bottom of the screen and change the duration
there, there are no Smart Tags (feedback indicators) appearing.

I hope this helps. Let us know how you get along.

Julie
Project MVP

Visit http://project.mvps.org/ for the FAQs and additional information
about Microsoft Project

 

[Brian Lukanic]

Julie,

I have not been able to re-create my error since that first day I reported
it. Although it was repeatable many times during that session, I too am now
seeing it behave as expected.

At this point I am either going to consider it a user error or a one-time
glitch.

But in a related question: When Project increases (by recalcuation) unit
values on multiple assignments for a task, how does the app decide which
resource's unit values to increase? For instance, let's say I edit the fixed
work's duration to force my resources to work a larger % of their time...
Both started at 15%, but after my shortened duration, resource A stays at 15%
but resource B gets recalculated to 19%. What creiteria does Project use to
decide who works more?

 

[JulieS]

Hi Brian,

I'm glad to hear the glitch has disappeared .

To your new question. I'm afraid I don't have the *complete* answer but a
number of factors play into the issue including resource calendars, and who
is the "driver" resource.

For example:
A fixed work task type with two resources assigned at 100%.

Bob is scheduled for 16 hours of work with 100% assignment units
Mary is schedule for 4 hours of work with 100% assignment units.

The task duration is 2 days. Although Mary is assigned to a task with a 2
day duration, she actuallly finishes her work 4 hours into the 2 day
duration. If I drop the duration of the task to 1.5 days, Bob's unit
assignment increases to 133% but Mary's stays at 100%. Bob still has the
accomplish his 16 hours of work but now in less time (duration). Mary is
still able to accomplish her 4 hours of work at 100% assignment units.

Another example with a different twist.
1 Day duration task schedule for Monday
Bob is assigned at 50% with 4 hours of work
Sue is assigned at 50% with 4 hours of work. But Sue's working calendar has
been change that she only works Monday, Wednesday, and Friday.
The task is fixed work.

I change the duration to 2 days.
Bob's assignment units drops to 25%. He is now going to do 2 hours of work
on day 1 and two hours of work on day 2.
Sue's assignment units stays at 50% with 4 hours of work. Sue's assignment
units didn't change as Tuesday (day 2) is a non-working day.

I change the duration to 3 days.
Bob's assignment units is 17% work is still 4 hours spread across 3 working
days.
Sue's assignment units is 25% work is still 4 hours spread across 2 working
days.

As I suggested, I work with the Task Form visible to be able to see
assignment units, work, and duration for resources.

I hope this helps. Let us know how you get along.

Julie