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Duration not accurate for summary tasks.

Foreslået svar Duration not accurate for summary tasks.

  • Monday, June 04, 2012 12:09 AM
     
     
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    This has been driving me nuts.  I can't get the summary tasks to accurately roll-up the tasks beneath it.  One thing that I noticed is the summary tasks always have "Task Type: Fixed Duration".  I cannot change this in the summary task, since it's grayed out.  I have "Fixed Units" selected as the default in the project.  Other bit of info, the tasks are all in Auto-schedule mode.  I am at a complete loss.

    Task Name Work Duration
    Env 1 (DCS SPS 2010 Development) 22 hrs 35.67 hrs?
       Backup Content DB from MB SPS 2010 Production 1 hr 0.13 days?
       Migrate backups to DCS development 2 hrs 2 hrs?
       Restore Content DB to Env 1 1 hr 0.13 days?
       Provision new Web Application 1 hr 0.13 days?
       Deploy customizations 4 hrs 0.33 days?
       Deploy third-party features 2 hrs 0.13 days?
       Attach Content DB to Web Application 1 hr 0.13 days?
       Configure farm services manually 4 hrs 4 hrs
       Review upgrade logs 2 hrs 0.25 days?
       Validate sites & fix issues 4 hrs 0.5 days?

    Thanks,

    Peter

     

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  • Monday, June 04, 2012 3:55 AM
     
     
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    >> One thing that I noticed is the summary tasks always have "Task Type: Fixed Duration".  I cannot change this in the summary task, since it's grayed out.

    You cannot change task type of a summary task. Pls see the article here: http://office.microsoft.com/en-us/project-help/dig-deeper-into-scheduling-RZ001077906.aspx?section=9

    A summary task always has a Fixed-duration task type. A summary task is based on the earliest start date and the latest finish date of its subtasks, and the calculation for a summary task's duration is based on its subtasks. So, you cannot directly change duration for a summary task.

    >> I can't get the summary tasks to accurately roll-up the tasks beneath it.

    How do you expect summary tasks to roll-up the subtask durations ? Fractional durations can be resulted from editing the assignments (just one of the possible reasons). Is this your schedule ? I mean, do you know the history of modifications or updates ?

    Pls also see the discussion Why does the task total come up as a fraction of a day?

     
  • Monday, June 04, 2012 4:26 AM
     
     
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    Thanks for the reply and links.  The schedule in my question shows the duration greater than the work hours, even though I have multiple resources assigned to certain tasks.  In my question above the sub-tasks each have the same amount of work and duration, but when rolled up the duration is greater.  I don't understand how this could happen if there is 1 more resources assigned to a task @ 100%.

    Thanks,

    Peter

     
     
  • Monday, June 04, 2012 5:55 AM
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    Hi Peter,

    Summary Duration field gets calculated as Finish-Start, so even if sub-tasks duration are less but there are some lag/lead defined between them which is shifting the over-all finish date of summary task -> it will be used to calculate Summary duration. Hope this helps. Work gets it value from total effort exercised by resources on sub-tasks based on their duration (& number of resources).

    Sapna S


     
  • Monday, June 04, 2012 11:45 AM
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    Peter,

    Are your tasks still mixing task calendars?  If the subtasks are using the 24 hours calendar and the summary is using Standard, you will get this issue.  Zip the project and email it to me at prjng@maine.rr.com.  I'll take a look at the specifics.

    Julie

     
  • Wednesday, June 06, 2012 12:07 AM
     
     
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    I'm having the same problem. It happens like this:

    Summary task has correct start and finish dates based on tasks beneath it. Tasks are a mix of manual and auto-schedule. I edit the task with the earliest start date to have a later start date. Summary task updates its start date to project start!

    All tasks use the project calendar, with no exceptions.
    Using Project 2010.

    TIA,
    Brian

     
  • Thursday, August 09, 2012 4:21 PM
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    Please re-post if this is still an issue..

     
  • Wednesday, August 22, 2012 1:06 AM
     
     
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    Hi Mike,

    Yes, it's still an issue. It seems to be related to use of auto-scheduled tasks, and messing around with dates/durations of them.

    While I'm on the subject, another oddity: sometimes the Summary task "freezes", i.e., it doesn't change no matter how I change the dates/durations of the tasks beneath it. The only solution I've found is to create a new (manual) task beneath the summary line, and then "promote" it to become the new summary task, which takes the correct dates/duration. Then I delete the old summary task.

    Any thoughts?

     
  • Wednesday, August 22, 2012 3:08 PM
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    Hi Brian,

    I have no definitive answer.  However, you should not be entering Start or Finish dates as by doing so you will automatically create constraints.  The best way for Project is to enter Tasks and their Durations. Then enter the predecessors (logic links) whence Project will do what it is designed to do - calculate the dates and give you a schedule.  When you're satisfied with this schedule, you then enter Resource names and assign them to appropriate tasks.  Unless you change the default calendars, Project will assume each Resource will work 8 hours per day and thus calculate the Work hours based on the Durations.

    To check what has happened in your case, insert the Constraint column set the top one to As Soon As Possible (which means no constraint) and fill down to all the others. See what that result gives you.  Check also in Project Information that you have the default calendar selected.  Make sure that there are no resource or task calendars in use.

    Try that and let us know how you get on.

    Mike Glen

    Project MVP (97-11)

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


     
  • Wednesday, August 22, 2012 5:01 PM
     
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    Brian,

    In several instances the summary task freezes if the start and finish dates of the subtasks under it are manually changed. Please avoid manually changing the start and finish date. Also manually editing of dates adds constraints to the tasks.

    In the plan, having the summary tasks with inaccurate duration,what happens to the duration if you outdent all its subtasks and than indent the subtasks again.

    Did you add any predecessor, successor or resource to summary task?

    Do the subtasks have predecessors?
    Do the subtasks have constraints other then ASAP?

    Thanks and Regards, Roopkumar Kamat (MCITP)

    • Proposed As Answer by Brian Herzog Thursday, August 23, 2012 1:35 AM
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  • Thursday, August 23, 2012 1:35 AM
     
     
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    Mike and Roopkumar,

    First of all, thanks very much for taking the time to post your thoughtful responses. It's much appreciated.

    Mike, I understand and agree with the approach you suggest to setting up the tasks. It's (mostly) the the way I do it. The problem with that approach appears when tracking a project and updating how long the tasks actually take. It's not possible to simply go in and modify the finish date of a task manually: things go haywire. The only approach I've found that works, is to adjust the duration amount by trial and error until it results in the finish date that I want. Rather kludgy, don't you think?.

    Roopkumar, it sounds like you've correctly diagnosed what's happening to me. So it looks like I'll have to continue to use the updating method described above. To answer your specific questions:

    > Did you add any predecessor, successor or resource to summary task?

    I do not add predecessors or resources to any summary tasks, but I do have successors to my summary tasks. Any reason this should be a problem?

    > Do the subtasks have predecessors?

    Not always, but usually.

    > Do the subtasks have constraints other then ASAP?

    Not when they have predecessor(s). But subtasks with no predecessor have manually-set start dates, which is a "No Sooner Than" constraint, yes?

    Thanks again,

    Brian

     
  • Thursday, August 23, 2012 11:47 AM
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    Brian,

    The best way to update tasks is to enter the Actual Work and Remaining work data and let Project re-work the schedule for you.  I repeat, it's best not to enter dates at all because of the constraints that Project will apply.  Although written for up to 2007 versions, the principles still apply in my free series for beginners on Microsoft Project in the TechTrax ezine, particularly #25 et seq on Tracking and Progressing, at this site: http://tinyurl.com/2xbhc  or this: http://pubs.logicalexpressions.com/Pub0009/LPMFrame.asp?CMD=ArticleSearch&AUTH=23 (Perhaps you'd care to rate the articles before leaving the site, :)  Thanks.

    Summaries should never have predecessors or successors in my view because they are not real tasks, and all sorts of logic problems could arise, including circular references.  See FAQ #48 here: http://www.mvps.org/project/

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

    Mike Glen
    MS Project MVP (97-11)

     

     
  • Thursday, August 23, 2012 1:55 PM
     
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    After reading all the answer, I'm at a lost to see if this was resolved.  I am having a similar issue.  I have a summary task (it's a task period) that has subtasks.  And the subtasks are all manually entered (because they are after the fact) and their start end dates are not sequential.)  I put in the dates manually because I know when the work was done and now I simply want the summary task to total the duration (days of work) correctly (not based on the dates (which is does correctly update from the subtasks.)  But for some reason the summary's duration doesn't total by adding the manually inputted durations of the subtasks.

    Is this normal?  Do I have to also manually update the summary task's duration???

    JEL

    • Proposed As Answer by Roopkumar Kamat Thursday, August 23, 2012 7:24 PM
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  • Thursday, August 23, 2012 7:21 PM
     
     
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    The only reason I recommend to avoid the successor to summary task is that if the summary task calculation freezes then its successors dates will not change even though the tasks schedule under the summary task has changed.

    As you mentioned the tasks having constraints do not have predecessor . But if its start date is earliest or finish date is latest than the other subtasks under the summary task, the duration of summary task will change.

    Thanks and Regards, Roopkumar Kamat (MCITP)

     
  • Thursday, August 23, 2012 7:37 PM
     
     
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    mimi,

    You cannot manually update the summary task duration. It is calculated as finish- start.

    If you want to just show sum of the duration of all the subtasks in summary task follow the workaround below:

    1. Add a column named Duration1.

    2. Right click on Duration1 field name in the header column.

    3. Click on Custom fields. In custom fields dialog box, click on Formulas button. In formula box add field name  [Duration] click Ok.

    4. In custom fileds dialog box, select the Rollup option and select Sum from the drop down menu. click Ok

    Thanks and Regards, Roopkumar Kamat (MCITP)