Date Calculation

[Cindy]

I have created a project with a 24 hour calendar and edited the start and end
times for the tasks.
I have a task that has a 14 day duration, based on its predecessor it should
start on 12/7/04. Project is calculating its end date as 1/4/05. This
definately is more than 14 days. I have reveiwed the calendars,
predecessors, constraints and everything I can think of.
In addition, in another section of the project I have another task that has
a 60 day duration that starts 1/4/05 and ends on 5/4/05. Again the calendar
is set at 24 hour, 12:00 am to 12:00pm.
I am using fixed duration and have unchecked effort drive.
thanks,

 

[Ian Coletti, PMP]

Hi Cindy.

Fun with calendars!

First, which calendar did you set to 24 hours? Or... did you use the
built-in 24 hour calendar? If you changed the "standard" calendar, make sure
your set the start and end times using the "Change Working Time" function
(Tools | Change Working Time), select Standard (or whatever calendar you want
to use) in the "For:" dropdown list, and select all days of the week in the
"Select Date(s):" section (kind of works like Excel by clicking and dragging
across all days in the week).... then set the time to 12 AM to 12 AM. This
will ensure that this calendar is 24 hours x 7 days per week (unless you want
5 days per week... so you would need to not select Saturdays and Sundays).

Next, verify that both your resources and tasks are set to use this calendar
by default (unless you want to check assignment by assignment). For tasks,
insert the "calendar" column in a Gantt view and you can easily set the
calendar. For resources, set their default calendar to your customized
calendar (or the 24 hour calendar) using the resource sheet.

Also, check resource assignments and their % allocation to a task. The
order in which you set the task type, assign resources, and adjust % units
could affect the duration.

BTW, by using the "fixed Duration" task type, either checking or unchecking
"effort driven" only affects work for a task and then only affects it when
you either add or delete a assigned resource to a task. It will not affect
duration for this task type..

There are lots of possibilities to your quandary!

Best of luck!

Ian

 

[Steve House [MVP]]

There're several issues to be explored here. Remember duration is the
amount of working time units designated by the calendar between when work is
first performed on a task and when it ends. It may or may not be
continuous. If a task starts Dec 07 and goes for 5 days, then is
interrupted for a few weeks (perhaps the holidays are shown as non-working
time, a 2 or 3 week stand-down) and then resumes, working for another 5 days
and then it's finished sometime in January the elapsed time is more than a
month but the duration is still only 10 days because the time off in the
middle for the holidays doesn't count.

An alarm bell is going off when you say you "edited the start and end times"
for the tasks. When you edit either one you inevitably establish
constraints on the task, constraints that are rarely justifed. If you edit
the start, you get a Start No Earlier Than constraint. If you edit the end,
you get a Finish No Earlier Than constraint. If you edit BOTH, the
constraint you get is determined by the order you do the edits. BUT, you
really shouldn't be doing either one! The whole reason Project exists is to
calculate the schedule for you - you don't tell it the dates where it should
schedule the tasks -- you tell it what needs to be done, the relationships
between the tasks, the resources you have to do them with, and how long each
should take and then it tells YOU the dates you can have them on, a whole
different paradigm.

I'd suggest you be very, very careful about using the 24 hour calendar as
you are. Doing so implies that when your 60 day task begins, work on it
never stops for over 2 months, the resources doing the work never sleeping,
never eating, never getting a day off for that entire period of time.
People simply don't work that way. The project calendar should describe the
hours during the day that work will take place on a typical task as
scheduled for a typical resource. While your company may very well work
24/7, a single person most certainly does not and the tasks should usually
describe the work done by a sigle person or a team working together as a
unit. If your "standard" shift is M-F, 8-5 that should be your project
calendar even if you really have multiple shifts working in the aggregate
24/7. If you have a task "dig a hole" and you assign that task to Joe
Dayshift, the hours that Joe works are the only one's that matter - it is
totally irrelevant that there is also Bill working Swing shift and Fred
working Graveyard, they're not digging the hole, only Joe is, and the
calendar that governs the scheduling of that task should be Joe's work
schedule and Joe's alone. The project calendar governs task placement's
until you assign resources and so, IMHO, it should be the work shift of a
typical resource, not the company as a whole.

HTH