Project 'late as possible'

Discussion in 'Project General' started by DCBanks, Mar 30, 2007.

  1. DCBanks

    DCBanks Guest

    I have task 1 linked to task 2 as a 'finish to finish' so they both finish on
    the same day. Task 1 has a number of predecessors all with 'finish to start'
    links. I want these predecessors to back off from task 1 so I have made them
    all 'as late as possible' but they take that as the latest date on my whole
    project. I want them to take the 'late as possible date' as being the Start
    Date of task 1 - ie the one they are linked to.
    I cant make the whole project ALAP as 95% is ASAP. In other words I want the
    predecessors to be 'just in time'.

    David
     
    DCBanks, Mar 30, 2007
    #1
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  2. DCBanks

    Jim Aksel Guest

    You can add a constraint to Task1 such as "Start No Later Than" and give it a
    date.
    However, you should have a logical reason to establish such a constraint; if
    TaskA is a predecessor to Task1 and there is no other reason to force Task1
    to start, then it is perfectly reasonable to let TaskA finish drive Task1
    start no matter how late it becomes.
    --
    If this post was helpful, please consider rating it.

    Jim
    It's software; it's not allowed to win.

    Visit http://project.mvps.org/ for FAQs and more information
    about Microsoft Project
     
    Jim Aksel, Mar 30, 2007
    #2
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  3. DCBanks

    John Guest

    David,
    Project is not very good a setting up a "just in time" schedule. However
    for the scenario you described I could set up a test file that does what
    you want. For simplicity it has no resources and the following structure.

    ID Name Cons Dur Start Finish Pred
    1 Task a ASAP 10 3/30/07 4/12/07
    2 Task b ALAP 10 5/9/07 5/22/07 1
    3 Task c ALAP 10 5/9/07 5/22/07
    4 Task d SNET 10 5/9/07 5/22/07
    5 Task e ASAP 20 5/23/07 6/19/07 2,3,4
    6 Task f ASAP 20 5/23/07 6/19/07 5FF

    Task 4 was put in to test that tasks 2 and 3 indeed shift as far right
    as possible and still honor the link with task 5.

    I won't guarantee that is structure will work in all cases, but it does
    appear to work for your described structure.

    John
    Project MVP
     
    John, Mar 30, 2007
    #3
  4. Hi,

    I've been asking for that development for the past 6 years and Ipromise you,
    I shall go on asking as long as the lab asks for my input. I'm almost ashame
    to admit that there is no good solution for JIT. There simply isn't.
     
    Jan De Messemaeker, Mar 30, 2007
    #4
  5. DCBanks

    DCBanks Guest

    Thanks for your suggestions. There are only two dates on my plan, the project
    start date and finish date. All tasks are either ASAP from the start date or
    ALAP to the finish date, I do not believe in 'hard coding' dates as this
    destroys the planning part of Project - 90% of this project is internal with
    a few supplier 'promise' dates.
    However, I have found the answer. I make the last task in the sequence FF to
    the next milestone. Then I reverse the usual logic and work backwards from
    the last task, making it 'Start to Finish' with the previous task. This works
    until I get to the first task in the sequence which is driven by a previous
    ASAP milestone. This way I can find my slack which is the difference betwen
    the driving milestone date and the FF date of my next milestone - and sure
    enough when these dates get closer my slack decreases - just what I wanted.
    What happens when I have minus slack, well there's always the bottle or a
    loaded gun!!!
     
    DCBanks, Apr 2, 2007
    #5
  6. DCBanks

    John Guest

    David,
    You're welcome and thanks for the feedback. I didn't actually try your
    approach so I can't say if there are any disadvantages. However, if it
    is working for you then it can't be too bad.

    John
     
    John, Apr 2, 2007
    #6
  7. DCBanks

    David Banks

    Joined:
    Nov 6, 2017
    Messages:
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    Hello, I can't believe it, I asked the same question today (6/11/2017), read this thread and didn't realise till I got to the bottom that I had already answered it myself - 10 years ago. Has Microsoft really NOT implemented JIT yet - surely if Project detects a minus lag why can't it 'back-off' from the successor. All it has to do then is give a scheduling warning when the total slack of the sub-task gets to -1 day.
    David
     
    David Banks, Nov 6, 2017
    #7
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