Summary tasks' duration with partial days

[PRibeiro]

Dear All:
I am facing a puzzling problem when preparing a project.
I have summary tasks to add up the duration of segments of the project.
All sub-tasks have complete work days. The schedule is Monday-Sunday
(9:00-18:00) without rest days or holidays. The fact is that the summary
task comes with partial days in the duration (ex. 26.56 days), which is
really puzzling me as I cannot find any reasonable explanation for this
to happen.

Thanks in advance for your help.

 

[Rob Schneider]

I suspect you are mixing up duration with work. Work is the amount of
time spent on a task, e.g 12 days over a two day duration, e.g. then 6
units of full time people required. Summary duration will be the, for
the collection subtasks, the number of work days (defined by the
calendar) between the the earliest start and latest finish. Best way to
debug your schedule is to:
: read in help about the difference between work and duration
: display the start/end dates with time shown so that you can see where
perhaps you have some tasks start and/or end dates not being exactly
what you expected. I suspect one or more are spilling over or falling
short of integer days.

 

[Mike Glen]

Hi PRibeiro,

Welcome to this Microsoft Project newsgroup

I suspect a mis-match between calendars and settings. You might like to see
FAQ Item: 5. Default Working Hours

FAQs, companion products and other useful Project information can be seen at
this web address: http://project.mvps.org/faqs.htm

Hope this helps - please let us know how you get on

Mike Glen
Project MVP
See http://tinyurl.com/2xbhc for my free Project Tutorials

 

[PRibeiro]

Thanks a lot for your replies. I found out where the "error" lies, but I
still cannot find explanation for it.
The problem is when I have contraints types in the tasks "Start No
Earlier Than" . If I remove that contraint and put "As soon as possible"
then the summary task goes to entire days. Finding the "solution" is ok,
but I don't understand why a constraint of this type, with tasks with
entire days duration can provoke partial days in the summary tasks. Any
clue?

Rob: I believe that there is no confusion between work and duration as
I didn't even defined resources in the project.

 

[Rob Schneider]

Thanks a lot for your replies. I found out where the "error" lies, but I
still cannot find explanation for it.
The problem is when I have contraints types in the tasks "Start No
Earlier Than" . If I remove that contraint and put "As soon as possible"
then the summary task goes to entire days. Finding the "solution" is ok,
but I don't understand why a constraint of this type, with tasks with
entire days duration can provoke partial days in the summary tasks. Any
clue?

Rob: I believe that there is no confusion between work and duration as
I didn't even defined resources in the project.

What do the start/finish date/times look? Perhaps by displaying time in
that information (in addition to date) you can see where you move into
durations where they are no longer integers.

 

[PRibeiro]

Hi Rob:
Thanks for your help.
I was looking in the Project menus but I couldn't find where can I add
the start/finish time. I can only find the usual Start/Finish date. Can
you please explain me where can I get this information?
Thanks in advance for your help.

 

[Mike Glen]

The Start No Earlier Than constraints have probably come from entering in
Start Dates. Don't do this - let Project calculate the dates for you from
the Durations and Predecessor links. The discrepancy probably comes from a
task starting at 0800 rather than 0900 (or the other way round). Both the
daily start and finish times in the calendar you set up in Change Working
Time... and the Tools/Options.../Calendar tab have to match. In
Tools/Options.../View tab, change the Date Format to one that contains
times.

Mike Glen
Project MVP
See http://tinyurl.com/2xbhc for my free Project Tutorials

 

[Rob Schneider]

Hi Rob:
Thanks for your help.
I was looking in the Project menus but I couldn't find where can I add
the start/finish time. I can only find the usual Start/Finish date. Can
you please explain me where can I get this information?
Thanks in advance for your help.

Menu: Tools/Options, Tab: View, pick "Date Format" to show time and dates.

There is no special fields for start/finish time. Time (dates and clock
time) are stored in the Project database as "minutes". Project just
displays this information as you define in the option above.

I was pointing you to this so that you would (probably) discover for
yourself what it is Rod tells you about (see his reply).

 

[PRibeiro]

Hi Mike:

Maybe you are right as I never set up constraints, so the system is
setting it up by itself. I usually only define the start date for the
project, and then work out the predecessors. Now, you say that it might
be the calendar defined working time, but I cannot understand why a
calendar where all tasks have the same working time (eg. 8.00-17.00)
calculates the duration of summary tasks differently from a calendar
with working times of 9.00-18.00h.
Also, sometimes I have constraints of starting dates for some tasks,
even if these are not linked to another task.

 

[Steve House]

All date fields, including constraints, are date/time fields. If you set
the display format to show time and look at your constraints, I'll wager
that although your workday starts at, say, 8am, the constraint is some othe
time. If there's a Start No Earlier Than constraint of a task at, say,
June15 10am, and the constraint is controlling the scheduled start, a 1 day
task starting on the 15th will finish a couple of hours into the 16th, not
at the end of the 15th, causing everything downline to be offset by several
hours. See the calendar options page, default start time, to see the
default time that will be entered into manually entered date values,
including constraint dates.

Be aware that is is actually impossible to use single day or full day
durations in Project. Durations are ALWAYS stored and calculated in minutes
to the nearest tenth. The other time units are allowed only for user
data-entry convenience. A "day" is defined as X minutes, found on the
calendar options page, not a sunrise/sunset or a 24 hour elapsed time
period. If anything causes a start to occur later than the start of the
workday, offsets will enter into the picture. A "1-day" task starting
Monday later than the start of the workday will finish on Tuesday. Since
the duration of a summary is the time between when the earliest starting
child begins and the latest finishing child ends, all manner of durations
can show up in the summary. Why does it matter?