Steve
Sat Mar 15 16:27:41 CDT 2008
Work is additive but duration is not. The duration of a summary task (your
"main task") is the time between when the earliest starting subtask begins
and the latest finishing subtask ends. Consider these examples ...
Summary task consists of 3 subtasks, each of which lasts 1 day. Each
subtask is to paint a picture of something. We can work on them in any
order. If I have 3 artists we can do them all on 1 day, the three artists
working in parallel. The total work is 3 days but the duration of the
summary task is 1 day. Or if we only have 1 artist, now only one picture at
a time can be worked on. Total summary work is still 3 days but its
duration has now also become three days.
We're not painting pictures but are painting a room. It takes 1 day to put
on the primer coat which then has to dry for 3 days before we can put on the
colour coat. The colour coat also take a day to apply. Task 1 lasts 1 day,
then there's a 3 day lag time, then Task 2 takes 1 day. No one has to sit
and watch the primer dry so there's no work being performed over the lag
time. The total summary work is 2 days but the summary duration is now 5
days, the total time between when work began on the primer coat and when
work finished on the colour coat.
HTH
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit
http://project.mvps.org/faqs.htm for the FAQs
"aamadure" <aamadure@discussions.microsoft.com> wrote in message
news:50E59A8F-6699-4465-984D-65DEA0C13932@microsoft.com...
> Dear B Sai,
>
> i believe i understand. it's just confusing to look at.
> The hours column is totaling correctly, but the duration column simply
> looks
> funny.
>
> I have 1 task with 6 subtasks that are to be completed in 1 day.
> In the DURATION column all subtasks are marked with "1 day?".
> The main task says "6 days?"
> The WORK column has hours allotted to the 6 subs and totals correctly.
>
> 1. Is it supposed to look like this.
> 2. If so it is confusing.
> 3. Might I not have all the tasks/subtasks sequenced properly?
>
>
>
> "B Sai Prasad [PMP]" wrote:
>
>> Dear Microsoft Office Project User,
>>
>> I wanted to share some insight about what Jack Dahlgren meant about "...
>> Duration of a summary task is based on the difference between the finish
>> date
>> of the last subtask and the first subtask.".
>>
>> As per your last reply, the sub tasks of the summary task are sequential
>> in
>> nature, and hence, the start date of the summary task is start date of
>> the
>> first sub task with the finish date of the summary task is finish date of
>> the
>> last sub task.
>>
>> In case, the subtasks are not sequenced then the start date of the
>> summary
>> task would be the minimum (start date of all its subtasks) and finish
>> date of
>> the summary task would be the maximum (finish date of all its subtasks).
>>
>> Duration of a summary task is the number of working days between its
>> start
>> date and finish date.
>>
>> Please let us know if this helps.
>>
>> Regards
>> Sai [PMP]
>>
>>
>> "Jack Dahlgren" wrote:
>>
>> > Duration is correct. It is NOT supposed to show the sum of task
>> > durations.
>> >
>> > -Jack Dahlgren
>> >
>> > "aamadure" <aamadure@discussions.microsoft.com> wrote in message
>> > news:E66633CC-6BA2-4991-B259-5817829B353D@microsoft.com...
>> > >I added the WORK column, and that totals hours correctly.
>> > >Unfortunately
>> > >the
>> > > Duration column is still showing an incorrect number of days. Do i
>> > > have
>> > > to
>> > > enter the days for the subtasks for this colmun as well?
>> > >
>> > > I have all tasks/subtasks linked Finish to Start, does that make a
>> > > difference?
>> > >
>> > > "Jack Dahlgren" wrote:
>> > >
>> > >> 1) ### is displayed when the column is not wide enough to show the
>> > >> value.
>> > >> Make the column wider to see the information.
>> > >>
>> > >> 2) Duration of a summary task is based on the difference between the
>> > >> finish
>> > >> date of the last subtask and the first subtask. If you have tasks
>> > >> which
>> > >> are
>> > >> not serial then the duration may not equal the sum of the subtask
>> > >> durations.
>> > >> If you want to see total work, insert the "Work" column. It should
>> > >> sum
>> > >> correctly.
>> > >>
>> > >> -Jack Dahlgren
>> > >>
>> > >>
>> > >> "aamadure" <aamadure@discussions.microsoft.com> wrote in message
>> > >> news:A954994F-F00B-4BA0-B7E8-97D77FC2886B@microsoft.com...
>> > >> > In my current project, I have entered all my Tasks, subtasks, and
>> > >> > resourses.
>> > >> > Here is my problem
>> > >> >
>> > >> > Some tasks are completed in 1 day (or 8h). These involve multiple
>> > >> > subtasks
>> > >> > that use different resources. The total time for all subtasks
>> > >> > totals
>> > >> > 8h.
>> > >> > (ex. task--plant tours = 1d, subtasks--freezer, warehouse,
>> > >> > processor,
>> > >> > packing =2h each)
>> > >> > PROBLEM: when i enter hours for subtasks the main task does not
>> > >> > total
>> > >> > correctly, I get ### or other odd items.
>> > >> >
>> > >> > Some tasks run 3-4 days, each subtask is equals 1 day. (ex.
>> > >> > task--work
>> > >> > with
>> > >> > drivers 3d, subtask--tom, dick, harry =1d each)
>> > >> > PROBLEM: when i enter days for each subtask the main task does
>> > >> > not
>> > >> > toal
>> > >> > correctly
>> > >> >
>> > >> > 1. How do I correctly enter hours for the subtasks so the main
>> > >> > task
>> > >> > totals
>> > >> > 1d?
>> > >> > 2. How do I enter days for subtasks so main tasks total the
>> > >> > correct #
>> > >> > of
>> > >> > days?
>> > >>
>> > >>
>> > >>
>> >
>> >
>> >