Changing Start and Finish Dates

[Té]

On my tasks I have 2 months to complete them, but they may only take 20 days
to finish. When I change the finish date to show a complete month my
duration changes. How can I set it up where the duration may be 20 days, but
my start and finish dates are 6/1/2008 and 8/1/2008. Please help!

 

[Jack Dahlgren]

Duration = Finish - Start.

You can not have a duration of 1 month and start and finish days two months
apart.

Which is the most likely duration for the task?

-Jack Dahlgren

 

[Té]

So there isnt anyway to set that up? We have 2 months to complete the tasks,
but the tasks may only take 20 days.

Also do you know anything about inserting subprojects? I have a master
project created and when I insert subprojects the duration on the project
summary task (master project) doesnt equal the other 2 subprojects. The
duration on subproject 1 is 30 days, and the duration on subproject 2 is 40
days, but the duration on the project summary task is 69 days. Why is this?

 

[Jack Dahlgren]

Do you think the tasks will take 20 days? Or do you think they will take two
months?
You can always set a deadline at the two month mark and set the duration at
20 days.
It all depends what you are going to use the schedule model for.
What are you hoping that your schedule will show you?

Duration of a summary task is equal to the difference between the start of
the summary task and the finish of the summary task. It is not the sum of
the durations of the sub-tasks unless those subtasks are serial with no
overlap. Looks like you may have some overlap.

-Jack

 

[Té]

I want it to show the full 2 months, but I want to be able to manually type
in 20 for the duration and it stays that way. Just for historical purposes I
want it to say 2 months, even though it may only take 20 days.

For my master project. Both subprojects start at the same time. And my
summary task duration still says 69 days, when in total it should be 70 days
because the start and finish dates of the summary task are the same as those
in the subprojects.

 

[Jack Dahlgren]

It either takes 2 months or 20 days. It can not take both.
That is just the way it is.

-Jack

 

[Steve House]

What you describe are 20-day duration tasks that have a deadline 2 months
after they're scheduled to start. Duration is defined as the elapsed time
the work will take with any intervening non-working time deducted. It is
not the "window of opportunity" but rather an estimate of the time that will
actually be required.

The duration of your project summary task is the time between when the
earliest beginning project starts and when the latest finishing project
ends. It might be the sum of the two durations but it is just as likely not
to be. If the subprojects overlap the summary duration will be less than
their total. If there's a gap between when the first one ends and the
second starts, it will be more than the sum. Sounds like there's a one day
overlap in your two projects.

 

[Steve House]

You just can't have it that way - it's sort of like the accountant who, when
asked for the sum of two plus two, answers "What would you like it to be?"
Duration is a defined term in project managment and you can't redefine it
any more than you can redfine the correct answer to 2+2. It's the amount of
working time as defined by the applicable calendar between the moment when
observable physical activity commences and the moment when the deliverable
is completed. It is positively NOT the time between between when work COULD
begin and the deadline by which it is required to be completed. It is the
estimate of the time reuqired between when it WILL begin and when it
actually WILL end. (And we try to make sure that is well in advance of the
finish deadline whenever possible.) A project schedule is a work schedule,
a tool to help you direct the work so deadlines are met. It is not merely a
list of those deadlines.

How could your total duration be 70 days if the two projects are starting
together, one with a duration of 30 days and the other of 40? Starting at
the same time means they both run in parallel. 30 work-days (6 weeks
typically) after they both start, the first one finishes. The other
continues on for another 10 work-days (2 weeks) when it too finishes. 40
work-days (8 weeks) after they began, BOTH projects are finished. Therefore
the total duration is 40 days. If your schedule is showing 69 days there's
a problem but it's not the one you think it is.

 

[Colin]

If this is just for record purposes, why don't you show the task for 2 months
- then take a baseline, then reduce the task to 20 days. Also, why not add a
deadline date, if there is one.

Colin