Split tasks: differtent calculation of duration RRS feed

  • Question

  • Hi,

    In our company some departments work during holidays, most of them don't. In the planning (no resources assigned, just Gantt bars to show what has to happen when) I want to clearly show which department has to work during holiday and which don't. To achieve this I do the following:

    I set the non working time to show behind the Gantt Bars. If a task starts a few weeks before a holiday, ends a few weeks after it and also takes place during the holiday, I just schedule the task and automaticcaly it shows over the non working time in the Gantt. If I would do the same for task which don't take place during the holiday but do before and after, I split the task in 2 and leave the first part up and running till the holiday and the second part from the first day after the holiday. So far so good. Maybe not the best way there is and if someone can point out a better way to do it, please feel free, but it does what I want it to do. Visualize what has to happen. Normally you just plan the task and show non working time before the Gantt, but since some taks has to happen during holiday I can't do this because otherwise they wont be visible. Better would it be to have an option to show specific tasks in front of non working time.

    But now something strange occured to me. I have several tasks where I used a split and which don't take place during holiday. In the Gantt I show the duration to the right of the bar. Now for some tasks it doesn't show the correct duration of a task. For example I have a task which lasts 2 times 3 weeks with a holiday in between. At the right of the second part it shows me  6 weeks as duration. But for another task, which is split over 1 part 30 weeks and 1 part 6 weeks and also a holiday in between it shows me 39 weeks. Seems it is taking into account the 3 weeks holidays in between. How is this possible or what is the logic behind this to don't count the holiday in the first duration an do it for the other one? I uploaded an image below. Clearly it takes over the duration field, but why can I specify a net duration in the first two tasks and split it around the holidays, and not for the second part. The second one shows 39 weeks but is net 36 weeks. When I change duration to 36 weeks, my Gantt displays net 33.

    Hope someone can help me out.

    • Edited by Peperbusse Wednesday, December 16, 2015 1:38 PM
    Wednesday, December 16, 2015 1:08 PM

All replies

  • Peperbusse,

    I've tried several things to try and replicate what you see but so far have not come up with any Gantt bar configuration that will add non-working time to a split task's duration. The one thing I do notice is that the color of the Gantt Bar with 39 wks duration is different from that showing 36 wks duration so I wonder if there is difference in the bar styles definition table that is causing the difference. If you use the exact same bar style for the 39 week task as for the 36 week task, does it still show 39 wks duration?

    Another issue I note is that if a user splits a task right at the day before a non-working period and attempts to move the second part to the day after the non-working period, Project will not split the task at all since that is exactly how a non-split task will appear anyway. In your second paragraph you indicate you run the first part up to the holiday and then start the second part the day after the holiday. That's not what your screen shot shows. It might help to know the stop and start date and times of the split. Note, these dates are not readily available fields and can only be accessed using VBA or clicking on the parts of the split task and noting the dates in the pop-up.

    Unless someone else has a ready answer, this may be a case of needing to see your file to determine what is going on. Would you be able to send me the file?


    Wednesday, December 16, 2015 4:23 PM
  • Hi John,

    Thanx for your reply. Your answer made me aware of the fact that the red Gantt bar above is exactly the same but has a different but correct duration. I looked deeper in the Task Information for both tasks and the only difference was the Task Type which was set on fixed duration for the incorrect one, and for the other one it was on fixed units. Changing the one with 39 weeks in fixed units dealed with the problem.

    About the other issue of splitting task up to the holiday and right after, I noticed this also when I created a new task. I took over this job from someone else who set up this schedule. Somehow the most bars with splits are finishing on the Friday before the holiday and starting on the Monday right after. If I want to reproduce this kind of split for a new task, MSP just turns it back into 1 Gantt bar again.


    Thursday, December 17, 2015 6:41 AM
  • Peperbusse,

    Indeed I didn't try different task types but now that I do, I get a difference in the duration (i.e. a fixed duration task will show a longer duration value).

    It sounds like the simple solution is to insure all task types are fixed work or fixed units even though you noted that you do not have resources assigned. Some VBA could be used to achieve the desired result for fixed duration tasks but with the easier fix, a macro isn't necessary.


    Thursday, December 17, 2015 6:28 PM