7 day calendar does not calculate the correct lag set on a milestone. RRS feed

  • Question

  • I have a series of tasks with a milestone grouping all the tasks to define the end of the activity.  The activity block has tasks that are both set with a normal standard calendar and a 7 day calendar.  There are no exceptions set to the 7 day calendar.

    The milestone is set to a 7 day calendar and a lag of 30 days is added.

    My problem is that the lag is not counting 30 calendar days, nothing I do changes it.  we have a commercial contractual requirement to provide documents 30 days after the completion of the work.  can someone shed some light on this issue please.

    I am using MS Project Professional 2010.



    Thursday, September 17, 2015 1:00 AM

All replies

  • Krys,

    When you say the milestone grouping of all tasks defines the end of the activity, do you mean that all tasks are predecessors to the completion milestone?

    Based on how I interpret your scenario I created this simple project. All tasks are predecessors to the completion milestone. Task calendars are set as shown although that will have nothing to do with the 30d lag. Note also that to achieve at 30 calendar day lag from the last task the lag must be expressed in elapsed days (i.e. calendar days). You will note that the milestone is indeed 30 calendar days after the last task.

    Does this approximate what you have? If not, what is different?


    Thursday, September 17, 2015 2:33 AM
  • Hi Krys,

    Is your project assigned with Standard calendar?

    If so, that might be the reason you cannot have a lag of 30 calendar days.

    You have pred. tasks with 7 day calendar but the timeline of the project is based on a 5 working days calendar, so the lag which is defined to work with working days is updating the milestone to the next 30 working days..

    Try to change the project calendar to be the 7 working days calendar and see if it reflects your needs.

    Ofir Marco , MCTS P.Z. Projects

    Thursday, September 17, 2015 1:58 PM
  • Assuming John's got your scenario right, then I can't think of a possible reason for a difference between using 30 edays or 30 working days (on a 7-day, no-exception calendar) for the lag.

    On the other hand, if you are looking for a 30-day lag AFTER the milestone and BEFORE another documentation task (on a 5-day calendar maybe), then the difference is expected.  Project (2003+) always computes lag using the calendar of the successor task - or the default calendar if the successor task has none.  You might not be expecting that.

    Regardless, John's suggestion of using elapsed days is a good one.

    Thursday, September 17, 2015 8:30 PM