Effort Driven versus Non-Effort Driven setting kick-in to control what
happens when you add or remove resources from a task. When you are editing
the parameters of work, units, or duration on the task without adding or
removing bodies it doesn't matter one way of the other, they have no effect.
Fixed Work, Fixed Units, or Fixed Duration setting control which of the
terms in the equation W=D*U are held constant when you edit one of the
terms. If you are changing a resource assignment from 100% to 50%, for
example, should Project recalculate the work required or the duration the
task will take? If it should recalculate work, make the task Fixed Duration
before you change the Units. If instead it should recalculate the Duration,
make the task Fixed Work before changing the Units.
In the original post Theresa said she had a task of 24 hours duration
spanning several months. That simply can't happen. If "several" means, for
instance, 3 months, the task doesn't have 24 hours duration, it has 3 months
duration. It may have 24 hours of work spread out over three months but the
duration is the time during which work might take place between the moment
something happens and the moment it's done even though the work doesn't take
place continuously. To get 24 hours of work over a 3 month time period, the
resource should be assigned at about a 5% assignment level. Using the
standard calendar for discussion, a month has 20 working days on average. A
working day is 8 hours. So 24 hours of work over 3 months means on average
1 day a month for the 3 month dfuration. 1/20 is 5%.
To make it interesting, You used the term "part-time." Things are different
if the resource works full-time but only spends part of his work-day on the
task in question versus works a part-time shift. If the resource is a full
time employee who works an 8 hour day and is expected to spend a couple of
weeks working on a task 4 hours per day, he has a regular 8-hour calendar
and is assigned 50%. But if he's a part-time employee who works 4 hours a
day and we expect him to devote his full attention to this task for a couple
of weeks, he is given a resource calendar that reflects he is "on the
property" as the railroads used to call it for 4 hours per day and he's
assigned 100% to the task. So in each case, Task X would have a Duration of
10 days, Work of 40 hours with either an 8-hour shift full-timer assigned at
50% or a 4-hour shift part-timer assigned at 100%. See, what the units
really represents is the rate at which duration gets converted to work. It
does NOT represent the percentage of a reasource's workday that he works on
the task although in the aggregate it may often work out that way. You can
see where it doesn't if you look at a 4 hour duration task. A full-time
worker assigned to that task who gets it done as fast as he can is working
on it 100% even though 4 hours is not 100% of his workday.
HTH
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit
http://www.mvps.org/project/faqs.htm for the FAQs
Dave Larkin said:
Thanks Steve - Sure, I understand Work/Duration, it's making Project
understand that's how I"m thinking that's been the problem.
I have it
almost licked but still getting suprises back from Project sometimes.
Unchecking "Effort Driven" is the key, but then does selecting and of
Fixed
Units/Duration/Work better match what I'm trying to do here?
Steve House said:
Be careful you don't mix up work and duration. Though they are both
measured in hours, they are totally different measures - as I like to
think
of it, duration measures the passage of time while work measures the
production of output. A task that requires 8 hours to be spread out over
a
week's time does NOT have an 8 hour duration. It has a 5 day duration
and 8
hours of work will be accomplished over the 5 day period. Duration is
the
time during which work could be taking place between when the first bit
of
work is done and the last. The work itself might start and stop numerous
times during that time period.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit
http://www.mvps.org/project/faqs.htm for the FAQs
Dave Larkin said:
I have the same issue as the original post; fixed dates and part time,
only
a
few hours
a day of an 8 hr day, between the start/end dates...
I tried your suggestion and that worked, but Project just scales back
the
resource to the required %, resets the duration to calender duration
and
rechecks the "Effort Driven" checkbox - which in less than ideal.
Is there a way to keep the part time duration and the start-end dates
fixed?
Dave
:
Hi,
I have a task that is 24 hours in duration spanning several months.
The
resource will work on the task as need be. There is an expected end
date but
when I enter the "fixed duration" in the advanced tab, the task
keeps
the 24
hours but the dates change to 3 days not the 2 month span.
Please help as most of our tasks in this project are like that.
Teresa
Teresa,
When you say the task is 24 hours in duration do you truly mean that
you
are on a 24 hour calendar, that is a working schedule of 24/7/365? Or
do
you perhaps mean that the total work content of the task is 24 hours
but
it will be accomplished on a part time basis over several months?
In order for a task to be true fixed duration, you also have to
uncheck
the "effort driven" option, otherwise once the task is entered,
changing
work or resources may change the duration even though it started out
as
fixed duration.
You say that most of your tasks are fixed duration. Why do you think
so?
Normally the duration of a task is determined by the amount of effort
required to accomplish it and/or the number of resources assigned to
it.
If the number of work hours increases, the duration tends to increase
also. On the other hand if more resources are added to work on the
task,
it will probably decrease the duration. Of course there is always the
adage that it still takes 9 months to make a baby no matter how many
women you put on it, so there are some cases where duration indeed is
fixed.
John
Project MVP
