Conflict with "Finish No Later Than" contstraint and when a task starts late.

[mttakimbo]

We have several types of task that need a "Finish No Later Than"
contstraint. I'm not sure how to get Project to reallocate resources
when the task is started later than expected.

For example, let's say we have a task that that must be complete by
10/24. We want to plan on having one resource work on it 2h a day for
10 days, starting on 10/11. This is 25% of the resource's units.

Now let's say that the first time the resource works on this task is
4h on 10/15, which is 2h behind schedule. When this is entered on the
timesheet, the Project Planning Wizard pops up stating that this will
create a scheduling conflict, because the program wants to push the
task finish date out another day.

Since my resource is only scheduled at 25% for the remainder of the
task (and is not scheduled in any other tasks or projects), why
doesn't Project just reallocate the resource to make up those 2h
during the remainder of the task?

Am I missing something?

The task is set as Fixed Work.

Thanks in advance,

Brian

 

[Andrew Lavinsky]

If it's Fixed Work, and you edit Work, then Duration will change (as you're
observing.)

Change it to Fixed Duration, and you shouldn't have that problem. You're
changing work, duration stays the same, and units goes up.

Eventually it will schedule one resource to work 30 hours in a day, but if
you're watching for things like that, it shouldn't be a major problem.

-A

 

[Andrew]

Oh yeah, and I guess there's an obligatory rap on the knuckles for posting a
Microsoft Project question in the Microsoft Project Server newsgroup.

 

[mttakimbo]

Andrew,

Thanks for the quick reply.

Though I thought we should use Fixed Work, I actually tried this with
Fixed Duration and Fixed Units and had the same problem.

If it's Fixed Work, and you edit Work, then Duration will change (as you're observing.)

Am I really editing work? I thought that entering 4h on 10/15 is
actually editing units. Instead of 25% on 10/11, 10/12 and 10/15,
there are no units used on the first 2 days and 50% on 10/15.
Therefore, the units on the remaining days should increase, duration
should decrease (because actual start date is now 10/15), with work
staying the same.

Project isn't changing the duration, its trying to move the start date
out, and keeping the duration and units the same. I want the duration
to get shorter and units to get higher.

We can't use Fixed Duration, because when the resource enters 4h
worked on 10/15, that day becomes the Actual Start date, so the
duration is getting shorter.

-Brian

 

[Andrew]

When you update the hours on the timesheet, or in the resource usage view,
you're updating Work. If the task is fixed units, and you update work later
than scheduled (as in your example), the end date will get pushed out - which
is often the desired calculation.

If the task is fixed duration, and you update work later than scheduled, it
will take the remainder of the work and spread it across the remaining
duration (which is fixed). In this case units do go up....correct.

And...now I see your point, Duration does decrease because my start date is
now later.....Remaining Duration does stay the same however. So Fixed
Duration actually means Fixed Remaining Duration (unless you started the task
on time).

We can't use Fixed Duration, because when the resource enters 4h
worked on 10/15, that day becomes the Actual Start date, so the
duration is getting shorter.

There's no other way to do it....since you're starting the task on 10/15,
the Actual Start has to be on 10/15. Task type won't matter as they will all
exhibit that behavior.

If you want the Baseline Duration, you can display that - or you can create
some sort of custom field measuring the duration between the Baseline Start
to the Finish fields....? Is that what you're looking for?

 

[mttakimbo]

What I am looking for is a way to make Project take the remaining 16
hours necessary to finish the task and spread them across the
remaining 7 days so the task gets done by 10/24. I want the Units on
those 7 days to go up.

 

[Andrew]

Then, I would set those tasks to Fixed Duration. Go into the Resource Usage
view, add hours behind schedule, (i.e. if 8 is scheduled, add 4), and see if
the units for the remaining work go up and the end date (not necessarily
duration) stays the same. That's how it should work.

Let me know if that works for you.....

-A

 

[mttakimbo]

Same problem.

I did notice that with Fixed Duration, Project will increase units if
the task is behind schedule as long as there is some work done on the
planned start date, so the actual start date does not change.

Training the team to enter 1 hour worked on the first day of the task
even if there was no work done could be a possible work around, but
that would defeat the purpose of keeping accurate timesheets. Plus
explaining to the PMs why they need to do this doesn't sound easy
either.

thanks again for taking the time.

Brian

 

[Andrew]

Your problem isn't a problem. It's a feature. The product rightfully
records the Actual Start as the first day in which hours have been posted. I
can't see any reason why that would be undesireable.

-A

 

[mttakimbo]

Its not undesireable to me for Actual Start to change. I rather that
it change, as that is what is really happening. The problem is
getting an error because Project wants to change the end date for a
task with a "Finish No Later Than" constraint instead of increasing a
resources units (which there are plenty of).

Understand what I am saying?

-Brian

 

[Andrew]

Well, I tested it out, and you're right. That is strange. Honestly, I never
noticed that happening in the past. I guess there's a reason for that
behavior, but am not sure what it could be.

That being said, I guess the way I would treat it is:

1) Create a filter for all tasks that have an Actual Start not equal to
Baseline Start
2) Create a custom field calculating the difference (ProjDateDiff) between
the Stop date and the Baseline Finish
3) Manually (or through a macro), copy that data into the Remaining Duration
column for the tasks causing the problems

And yes, you're right, you would need to set the tasks to Fixed Work for
this to work. After the Actual Start was populated, and you go through the
above procedure, changing them back to Fixed Duration would then meet your
needs.

If it's not a huge problem, I guess it's a manual training issue for the
PM's. If it is a huge problem, you may want to consider either a macro, or a
special view w/ a filter and a couple custom fields. Then, you would only
have to look at that view to see if any tasks are showing that problem. You
could even add a flag field and tie it to a filter, such that if you're ok w/
some of the tasks, you can just flag them so, and they won't appear in the
view.

Apologies for being so thickheaded, and thanks for teaching me something.

-A

 

[mttakimbo]

No need to apologize, I'm just glad you figured out what I meant.

I think I found a solution. For Fixed Duration tasks with a Finish No
Later Than constraint, setting the Actual Start to match Baseline
Start before there is any work done. Then when work is actually
started it won't matter if we are behind schedule because the Actual
Start will already be set.

thanks again,

Brian

 

[Gary L. Chefetz [MVP]]

Brian:

The tool behaves this way because it reschedules work at the same Max Units
as you provided during the original assignment.You can always switch to the
Task Usage or Resource Usage views and contour the remaining work as you
like, but you can't expect Project to do this for you. Setting the actual
start date might backfire on you. Rescheduling work within the remaining
duration requires more thinking than project can currently provide.

--

Gary L. Chefetz, MVP
MSProjectExperts
For Project Server Consulting: http://www.msprojectexperts.com
For Project Server FAQS: http://www.projectserverexperts.com