Duration driving Finish based on which calendar?

[Martin Wilkinson]

Thought I'd cracked Durations but it's got me again!

I'm using Fixed Duration with a shorter than Standard resource calendar and
I'm not getting expected Finish dates.

To demonstrate, if I have a single task, Fixed Duration, 75 days, starting 1
Feb 06. With the default Tools/Options/Calendar settings (8 hrs/day, 40
hrs/week, 20 days/month), the end date is 17 May 06. This is 75 working days
(weekdays), entirely as expected.

However, the Resource I want to allocate to it has a 32 hour working week
(and this is reflected in the Resource’s own calendar).

I therefore change Tools/Options/Calendar settings to be consistent with
this (6.4 hrs/day, 32 hrs/week, 20 days/month). The Duration changes to 93.75
days and the end date stays at 17 May 06. If I set the Duration back to 75
the end date goes to 26 April 06, which is wrong for the Resource’s shorter
working day calendar.

The behaviour above results whether or not I have a Resource allocated to
the task, and whether or not that Resource’s calendar is based on Standard,
or something with less then 40 hours/week. So the issue is with the
Tools/Options/Calendar settings, not with the resource or its calendar.

I want to be able to enter a duration in terms of my real, shorter than
standard 8 hour, working days and for it to calculate the end date as 17 May.

If I apply a Task Calendar defined as 32 hours/week, the end date is OK (16
May 75 days duration). The problem is, I don’t want to have to apply a Task
calendar to every Task in my schedule. It could also be very confusing to
other people using the schedule, because Task Calendars are a little bit
esoteric.

If I apply a Resource which is based on the shorter calendar, it makes no
difference (the shorter calendar of the resource does not affect the end
date).

I know Duration is Work/Resource units, but if there is 0 Work and no
resources allocated, on what basis does MSP calculate the end date from a
Duration? It looks like the Duration drives the end date using the Standard
calendar, regardless of the calendars of any Resources applied to the task.

The only thing I can think of is to change the Standard calendar Working
Time to 32 hrs/week. I don’t really want to do this because I am using a
resource pool used by several projects and I don’t want the shorter week
applied to all projects, just those tasks which have resources with a shorter
calendar.

Does anyone know any alternative to applying task calendars en masse, which
seems the least bad option at the moment?

Apologies if the above is confused. I have an example project if anyone
needs it.

Thanks

Martin

 

[Gérard Ducouret]

Hello Martin,
<<I therefore change Tools/Options/Calendar settings to be consistent with
this (6.4 hrs/day, 32 hrs/week, 20 days/month). >>

Never do that ! This paramater works at the porject level, not on a resource
by resource basis.

Gérard

 

[Gary L. Chefetz [MVP]]

Martin:

What happens when you deselect the checkbox for effort driven?

 

[Martin Wilkinson]

Thanks for replying.
I should have said I know that all the resources that will be applied to
that project will have the shorter working week, so I think I can change
Tools/options/calendar for the whole project.

 

[Catfish Hunter]

Your resource calendar is setting the work week the way you have this set up.
I have set all my resources to a 24 hour calendar and allow the task calander
to dictate the working time. In other words I make my resources available 24
hours a day. I have many different types of calendars set up to faciliate
this.
Question: Do you have your resources set high enough as to not force the
duration to go longer? View>Resource Sheet
Good Luck.

 

[Catfish Hunter]

I have all my task set to Fixed Work. This deselects the effort diven box.
I use fixed work so the resource man hours will not change. After I baseline
my schedule I export resource useage to Excell and set up progress curves. As
we update the schedule I can get actual percent complete.

 

[Gérard Ducouret]

Martin,

OK, if all the resources that will be applied to that project will have the
shorter working week, you can change
Tools/options/calendar for the whole project.
But if you share these resources with some other project, you can't change
their calendar, so I'm afraid you will have to use the task
calendar...That's not difficult.
To do that quickly, insert the "Task Calendar" column in any table.

Gérard Ducouret

 

[Martin Wilkinson]

Nothing i.e Duration, Work (0), Start and Finish remain unchanged.

 

[Martin Wilkinson]

I think I have a way through. Our default task type is Fixed Work as we tend
to estimate effort for a task, asiign a couple of people, and let MSP tell us
when it will finish.

We have a non-standard 32 hrs working week, this is reflected in
Tools/Options/Calendar and the resource calendars.

We have a couple of tasks (customer acceptance tests) which we know will
take a fixed duration. The immediate reaction is to make the task Fixed
Duration. However this causes the problem above.

If I leave the task as fixed work then enter Work then Duration, the
Resource % assigned to the task varies to satisfy the work & duration just
entered. The Duration is then consistent with our working week (i.e. entering
10 working days results in 10 working days between the Start & Finish dates).

 

[Steve House [Project MVP]]

The general duration logic goes like this (assume all settings and calendars
are at their defaults) ... Duration is the number of working time units
between when the task begins and when it is done. The basic working time
unit is really a 1/10 of a minute "tick" but for simplicity lets say it's
hours - and remember that ALL times are reduced to and calculated using
those basic units. You are allowed to makes duration entries and see their
values in days, weeks, etc only as a concession to convenience. You enter a
task starting 1 Nov with a duration of 10 days. MSP looks at the "hours per
day" setting on the calendar options page and from that conversion setting
it calculates that the task will last 80 working time hours and stores that
value as the duration in the task database. With no resources yet assigned
it looks at the Project Calendar and counts off working hours beginning 8am
01 Nov and determines when 80 working hours have been used up, skipping
every evening plus Sat and Sun as non-working time it calculates the task
ends at 5pm, 14 Nov. Now you assign a resource who works a 32 hour work
week according to his working time calendar - let's say he does that by
working 8 hours each day Mon, Tue, Wed, and Thu and is off Fri, Sat, and
Sun. The task still starts 01 Nov 8am and MSP still counts off the working
time units to finish but now the resource's calendar governs the count
instead of the Project Calendar and thus it skips Fri as well as Sat and
Sun. Now the 80 required duration hours doesn't get used up until 5pm on
Thursday 16 Nov. Note the Gantt chart STILL shows "10 days" because the
default setting says that every 8-hour chunk of working time is called a
"day" regardless of the sunrises and sunsets involved. Now reduce the
resource from 100% to 50%. He still must work 80 man-hours but he only does
it at half the rate. It takes him 160 hours of his total scheduled work
time to do the 80 hours of required work on the task so the task duration
changes to 160 hours or 20 days, reflecting how many hours he's on the
property to generate the required 80 total hours of work when only 50% of
his total time is devoted to the instant task.

Hope this helps
--
Steve House [MVP]
MS Project Trainer & Consultant
Visit http://www.mvps.org/project/faqs.htm for the FAQs