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Unit bug after recalculation RRS feed

  • Question

  • Hi

    Why can we read on"Ressources Name field" of Gantt Chart

    • Pers1[0,33]
    • Pers2[0,33]

    While on Task Usage View  it is displayed 0,5 day /person / day ?

    Thank by advance for your answer


    PS: Translation

    • jours = Days
    • j = jour = Day
    • Travail = Work
    • Durée = Duration
    • Début = Start
    • Fin = End
    • Nom de ressources = ressources name
    • Oui = Yes
    • Non = No


    • Edited by technet65 Monday, October 23, 2017 3:05 PM
    Monday, October 23, 2017 2:26 PM

Answers

  • technet65 --

    My name is Dale, but that does not matter.

    First of all, I would strongly recommend that you display Work values in Hours rather than in Days.  Keep in mind that Work and Duration are two entirely different values, and the default display of Work is in Hours, not Days.  I recreated your example but displayed Work in Hours rather than Days.  The amount of Work assigned to each resource is 24 hours, assigning each of them at a Units value of 100%, which gives a total of 72 hours for the task.  The Duration of the task is 3 days for this Fixed Units, Non-Effort Driven task.

    Next, I changed the Units value for R1 to 25%, for R2 to 50%, and left the Units value at 100% for R3.  Because this task is a Fixed Units task, this means that Microsoft Project will automatically recalculate the Duration of the task, not the Work.  The new Duration value is now 12 days, as you show in your sample.

    When I apply the Task Usage view, I can see that R1 is now scheduled to work 2 hours per day for 12 days from October 16 to October 31, as you show in your example. I can see that R2 is now scheduled to work 4 hours per day for 6 days from October 16 to October 23, as shown in your example.  I can see that R3 is now scheduled to work 8 hours per day for 3 days from October 16 to October 18, as shown in your example.

    So, the schedule for each resource is correct, the Duration for the task is correct, and the Work is correct for the task and for each resource.  So, based on this information, do you still have a question?  Let us know and we will try to help you.


    Dale A. Howard [MVP]

    • Marked as answer by technet65 Friday, October 27, 2017 4:28 PM
    Wednesday, October 25, 2017 5:26 PM
    Moderator
  • technet65 --

    Are you thinking that Microsoft Project should automatically transfer work from one resource to another to shorten the duration of the task?  If so, that is not how the software works.  The software has scheduled the work correctly for each of the three resources, based on the Units value you entered for each of them.  Obviously it will take R1 longer to complete his/her share of the work since he/she is working only 2 hours per day.  But the software WILL NOT transfer some of his/her work to R2 to shorten up the duration.  That is something YOU would need to do, my friend.  Does that help?  Let us know.


    Dale A. Howard [MVP]

    • Marked as answer by technet65 Friday, October 27, 2017 4:26 PM
    Wednesday, October 25, 2017 10:46 PM
    Moderator
  • TechNet --

    Please re-read my last reply.  What you are requesting is NOT how the software works.  Your Task Type setting is Fixed Units, which means that the Units value is locked so that Microsoft Project will not change it.  When you changed the Units values for two of the resources, the default programming of Microsoft Project tells the software to ALWAYS recalculate the Duration.  That is why you ended up with a Duration of 12 days.  It is not a proposed Duration.  It is the Duration the software says you will need to complete the task given the fact that two resources are working part-time.  As I said in my last post, the software WILL NOT transfer work from one resource to another to shorten the Duration.  You can do that if you want, but the software will not do it for you.  You can keep asking me the same question, but I am going to give you the same answer.  Hope this helps.


    Dale A. Howard [MVP]

    • Proposed as answer by John - Project Thursday, October 26, 2017 2:04 PM
    • Marked as answer by technet65 Friday, October 27, 2017 4:20 PM
    Thursday, October 26, 2017 12:54 PM
    Moderator
  • OK I understood why Ms Project proposes the duration below for

    • R1 = 12 days
    • R2 = 6 days
    • R3 = 3 days

    For each ressource, the work quantity is the same, 3 days

    So by default, Ms Project recalculates the duration in such a way that each ressource  works the same quantity

    • Marked as answer by technet65 Friday, October 27, 2017 4:05 PM
    • Unmarked as answer by technet65 Friday, October 27, 2017 4:20 PM
    • Marked as answer by technet65 Friday, October 27, 2017 4:24 PM
    Friday, October 27, 2017 4:05 PM

All replies

  • Hi,

    you see an behavior that was changed between versions 2007 and 2010. Assignement Unist after the name will always display assignment units from initially assigning resources and are not adjusted when units are recalculated. For more information see https://blogs.msdn.microsoft.com/project/2010/04/29/assignment-units-in-project-2010/

    Hope that helps?

    Barbara

    Monday, October 23, 2017 6:44 PM
    Moderator
  • Hi Barbara

    Thanks a lot for your response but in this example below, MS Project 2010 displays correctly recalculated units, that is very confusing. 

    Intial values

    Modification

    • Work is reduced to 1 day => Reduce units for the ressources (Diminuer les heures ouvrées pour la ressources)

    • Recalculated  Units per ressource are correctly refreshed

    Does your response explain this behavior?  

    Tuesday, October 24, 2017 8:10 AM
  • technet65 --

    Pardon me for bumping into this thread.  Suppose I assign a resource to a Fixed Work task at a Units value of 50% and a Work value of 40 hours.  Microsoft Project will calculate a Duration value of 10 days.  Then suppose I change the Duration value to 8 days.  Because the task is Fixed Work, Microsoft Project will recalculate the Units value.

    If you apply the Task Usage view, and then insert the Assignment Units and Peak columns, you will see what Microsoft Project how Microsoft Project handles the changes to the assignment.  The Assignment Units column displays the ORIGINAL Units value of 50%, while the PEAK column displays the NEW Units value of 63% after making a change to the assignment.

    The behavior you are seeing is a change Microsoft made in the 2010 version of Project to fix a long-standing bug that was in the tool in previous versions.  Although Microsoft did successfully fix the bug, the new behavior of the Units and Peak columns is confusing to most users.  But it is how the software works, and we need to live with it.

    Hope this additional information helps.


    Dale A. Howard [MVP]

    Tuesday, October 24, 2017 4:02 PM
    Moderator
  • Hi Howard,

    Thanks a lot for your help.

    I would like to use this opportunity to ask an explanation about recalculation.

    Initial values

    • Work = 9 days  with 3 resources with 100% unit ==> 3 days Duration


    Modification

    Work = 9 with pers1 (unit 0,25), pers2(unit 0,5), pers3(1) ==>  12 days Duration

    Question

    Could you explain me why MS project plans work until "ven 27 oct"  and not for example until  "Mer 25 oct" by adding 0,5 working days on "mar 24 oct" for  pers2?

    Thanks a lot for your help


    • Edited by technet65 Wednesday, October 25, 2017 2:44 PM
    Wednesday, October 25, 2017 6:54 AM
  • technet65 --

    My name is Dale, but that does not matter.

    First of all, I would strongly recommend that you display Work values in Hours rather than in Days.  Keep in mind that Work and Duration are two entirely different values, and the default display of Work is in Hours, not Days.  I recreated your example but displayed Work in Hours rather than Days.  The amount of Work assigned to each resource is 24 hours, assigning each of them at a Units value of 100%, which gives a total of 72 hours for the task.  The Duration of the task is 3 days for this Fixed Units, Non-Effort Driven task.

    Next, I changed the Units value for R1 to 25%, for R2 to 50%, and left the Units value at 100% for R3.  Because this task is a Fixed Units task, this means that Microsoft Project will automatically recalculate the Duration of the task, not the Work.  The new Duration value is now 12 days, as you show in your sample.

    When I apply the Task Usage view, I can see that R1 is now scheduled to work 2 hours per day for 12 days from October 16 to October 31, as you show in your example. I can see that R2 is now scheduled to work 4 hours per day for 6 days from October 16 to October 23, as shown in your example.  I can see that R3 is now scheduled to work 8 hours per day for 3 days from October 16 to October 18, as shown in your example.

    So, the schedule for each resource is correct, the Duration for the task is correct, and the Work is correct for the task and for each resource.  So, based on this information, do you still have a question?  Let us know and we will try to help you.


    Dale A. Howard [MVP]

    • Marked as answer by technet65 Friday, October 27, 2017 4:28 PM
    Wednesday, October 25, 2017 5:26 PM
    Moderator
  • Hi Dale,

    Thanks a lot for your response and your advise. I totally agree with you but I still don't undrestand why for :

    • R2 , the end date is not extended to 24 october with 0,5 units, corresponding to 30 and 29 october work of R1
    • R1, the end date is two days before, the removed work is transfered to R2 on 24 october

    hope that my question is tenough clear ?

    • Edited by technet65 Wednesday, October 25, 2017 9:51 PM
    Wednesday, October 25, 2017 9:34 PM
  • technet65 --

    Are you thinking that Microsoft Project should automatically transfer work from one resource to another to shorten the duration of the task?  If so, that is not how the software works.  The software has scheduled the work correctly for each of the three resources, based on the Units value you entered for each of them.  Obviously it will take R1 longer to complete his/her share of the work since he/she is working only 2 hours per day.  But the software WILL NOT transfer some of his/her work to R2 to shorten up the duration.  That is something YOU would need to do, my friend.  Does that help?  Let us know.


    Dale A. Howard [MVP]

    • Marked as answer by technet65 Friday, October 27, 2017 4:26 PM
    Wednesday, October 25, 2017 10:46 PM
    Moderator
  • Hi Dale,

    Thanks again for your help

    If I change units ressources as below

    • R1 = 0,25 instead of 1
    • R2 = 0,5   instead of 1
    • R3            unchanged

    And I want 9 work days, Ms Project proposes duration max = 12 days

    • R1 duration = 12 days => work =  3 days
    • R2 duration =  6 days =>  work =  3  days
    • R3 duration =  3 days =>  work =  3 days

                                              Total work  =  9 days

    But why does MS Project not propose this potential solution below with max duration  = 8 days

    • R1 duration = 8 days => work=   2 days (8 x 0,25 day)
    • R2 duration = 8 days => work =  4 days (8 x 0,5 day)
    • R3 duration = 3 days => work =  3 days (3 x 1 day)

                                             Total work  = 9 days

    So my underlying question is "what are duration recalculation rules ?"

    Thanks a lot for your explaination

    • Edited by technet65 Thursday, October 26, 2017 10:04 AM
    Thursday, October 26, 2017 6:08 AM
  • TechNet --

    Please re-read my last reply.  What you are requesting is NOT how the software works.  Your Task Type setting is Fixed Units, which means that the Units value is locked so that Microsoft Project will not change it.  When you changed the Units values for two of the resources, the default programming of Microsoft Project tells the software to ALWAYS recalculate the Duration.  That is why you ended up with a Duration of 12 days.  It is not a proposed Duration.  It is the Duration the software says you will need to complete the task given the fact that two resources are working part-time.  As I said in my last post, the software WILL NOT transfer work from one resource to another to shorten the Duration.  You can do that if you want, but the software will not do it for you.  You can keep asking me the same question, but I am going to give you the same answer.  Hope this helps.


    Dale A. Howard [MVP]

    • Proposed as answer by John - Project Thursday, October 26, 2017 2:04 PM
    • Marked as answer by technet65 Friday, October 27, 2017 4:20 PM
    Thursday, October 26, 2017 12:54 PM
    Moderator
  • Hi Dale,

    Please, forget everything about transfert. The initial situation is 

    • R1 = R2= R3 unit => 100%
    • Work  = 3 => Duration = 1

    I want 9 work days => max Duration = 3 with

    • R1 duration  = 3
    • R2 duration = 3
    • R3 duration = 3

    Until now I agree

    I change units ressources as below

    • R1 unit  = 0,25%
    • R2 unit  = 0,5%
    • R3 duration = 1 unchanged

    Why the max duration is 12 days and not 8 days, considering that both solutions are possible? Why does MS project favor solution with max duration = 12 days?

    What are the rules to arbitrate between the two solutions?

    Thanks a lot for your esponses

    • Edited by technet65 Thursday, October 26, 2017 3:14 PM
    Thursday, October 26, 2017 3:02 PM
  • OK I understood why Ms Project proposes the duration below for

    • R1 = 12 days
    • R2 = 6 days
    • R3 = 3 days

    For each ressource, the work quantity is the same, 3 days

    So by default, Ms Project recalculates the duration in such a way that each ressource  works the same quantity

    • Marked as answer by technet65 Friday, October 27, 2017 4:05 PM
    • Unmarked as answer by technet65 Friday, October 27, 2017 4:20 PM
    • Marked as answer by technet65 Friday, October 27, 2017 4:24 PM
    Friday, October 27, 2017 4:05 PM
  • technet65,

    Just for reference, I see you marked your own response as the answer when in fact Dale spent a fair amount of his time explaining how Project does the work equation calculation. You might want to re-consider who should get the credit for the answer.

    John

    Friday, October 27, 2017 4:12 PM
  • technet65 --

    Yes, you are correct.  And please unmark your own reply as the answer and mark one of my responses as the answer so I get credit.  Thanks!


    Dale A. Howard [MVP]

    • Proposed as answer by Rob Schneider Sunday, October 29, 2017 8:03 AM
    Friday, October 27, 2017 4:16 PM
    Moderator