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Change of Multiple Ressources in MS Project leads to unexpected behavior RRS feed

  • Question

  • I'm struggeling with MS Project Pro 2010. The duration of my fixed work task is not calculated correctly when working with multiple resources and different percentages assigned to it. I'll give you a simple example as I don't get the general behaviour behind the problem:

    1. Create a Fixed Work Task with a duration of 24 days

    2. Assign the Resource "R1"

    3. Change the resources to "R1;R2" => duration changes to 12 days as expected

    4. Change the resources to "R1;R2[200%]" => duration stays at 12 days although I would expect a new duration of 8 days

    5. Undo to step 2 and change resources directly to "R1;R2[200%]" => duration changes to 8 days as expected

    I get a lot of similar errors with multiple resources when using differnet percentages. Call me naiive but I would expect a predictible outcome depending on the entry in "Resource Names" :)

    Could you please tell me if that's abug or what I'm doing wrong.

    Best regards and thanks for your help!

    Frank

    Tuesday, June 5, 2012 4:28 PM

Answers

  • Hello Frank,

    When working with multiple resource assigned the duration of the task is dependent upon who finishes last.  To make things a bit easier to sort out, show the Task Form in the lower pane (View tab, check "Details").  So to show a bit more about what you are seeing:

    Step 2: Assigning R1 produces:  100% assignment units and 192 hours of work on the assignment.  The duration is not changed because all you did was assign the resource to a 24 day duration task.

    Step 3: You've now assigned R2.  Because the task is effort driven the 192 hours of work stays stable.  Now split by two resources each performing 96 hours of work.  The duration changes because both resources at 100% finish the task at the same time.

    Step 4:  Increase the assignment units of R2.  Now R2 is still doing 96 hours of work but because you have increased assignment units, the R2 resource now finishes the work earlier.  Because R1 is still plugging away on the 96 hours for that resource, the duration of the task remains unchanged.

    Remove all resources and change the duration back to 24 hours of work.  Because the task is Fixed Work the 192 hours of work was not removed.  You now assign Resource 1 and again all 192 hours of work is assigned to R1.  After making that assignment you assign 200% of R2 - now the work is still 192 hours in total but R1 is doing 64 hours and R2 is performing 128 hours.  All resources finish the task at the same time and the duration drops to 8 days.

    I hope this helps.

    Julie

    Tuesday, June 5, 2012 5:11 PM
    Moderator

All replies

  • Hello Frank,

    When working with multiple resource assigned the duration of the task is dependent upon who finishes last.  To make things a bit easier to sort out, show the Task Form in the lower pane (View tab, check "Details").  So to show a bit more about what you are seeing:

    Step 2: Assigning R1 produces:  100% assignment units and 192 hours of work on the assignment.  The duration is not changed because all you did was assign the resource to a 24 day duration task.

    Step 3: You've now assigned R2.  Because the task is effort driven the 192 hours of work stays stable.  Now split by two resources each performing 96 hours of work.  The duration changes because both resources at 100% finish the task at the same time.

    Step 4:  Increase the assignment units of R2.  Now R2 is still doing 96 hours of work but because you have increased assignment units, the R2 resource now finishes the work earlier.  Because R1 is still plugging away on the 96 hours for that resource, the duration of the task remains unchanged.

    Remove all resources and change the duration back to 24 hours of work.  Because the task is Fixed Work the 192 hours of work was not removed.  You now assign Resource 1 and again all 192 hours of work is assigned to R1.  After making that assignment you assign 200% of R2 - now the work is still 192 hours in total but R1 is doing 64 hours and R2 is performing 128 hours.  All resources finish the task at the same time and the duration drops to 8 days.

    I hope this helps.

    Julie

    Tuesday, June 5, 2012 5:11 PM
    Moderator
  • Thank you very much!

    I still find it a bit confusing but at least I get the logic behind it.

    Frank

    Wednesday, June 6, 2012 8:06 AM
  • Sorry to bother again but I guess this time I encoutered a bug regarding the same topic:

    1) Let's say I assigned the resources "R1;R2[200%]" to a Fixed Work Task with 24days of work. This results in 8d of work for R1 and 16d of work for R2.

    2) Now I would like to use 300% of R2 to speed up the task (R1;R2[300%]). As just changing the units of R2 won't change the previously assigned work I have to take a different approach:

    3) Using the entry table I delete R2 completly and hit Return: This leaves me with just "R1" and 24d of work assign to it. 

    4) Now I put my desired ressources "R1;R2[400%]" in the "Resource Names" field of the entry table. But this again results in 8d of work for R1 and 16d of work for R2. :(

    5) If I now repeat step 3 and 4 I end up with my desired work assignment (R1:6d / R2 18d). Therefore I conclude that the "R2[200%]" information was still kept somewhere in the memory, which led to the error in step 4.

    6) When I'm using the Task Form in the Split View for the editing in step 4 it works.

    Beside planing manually is there a better way to change the units (percentage) so all ressources work together on completing the whole task?

    I guess this is a common example as R1 and R2 could be employees of 2 differnet companies working together to completing a task (painting a house). When I figure out that I have to speed up the task there must be a simple way to just use some more people of company R2.

    Best regards

    Frank

    Wednesday, June 6, 2012 5:19 PM
  • Hello Frank,

    No bother at all.  Your question:

    Beside planing manually is there a better way to change the units (percentage) so all ressources work together on completing the whole task?

    is one that has caused much debate and much requests through the years.  The short answer is, no.  There is not currently any way when using multiple resources to guarantee that all resources begin and end their work at the same time.  Project schedules resources on tasks as if they are individuals, even if you use multiple units of the same resource.  As a suggestion that you may find more predictable, consider not using units above 100%.  Create separate resources and then I think you'll find the addition and subtraction easier to find.  For example:  instead of Programmers [500%], consider Programmer1, Programmer2, Programmer3, etc. 

    I am not a fan of using the Entry table for assignments -- I always use the task form -- it is much easier (in my opinion) to see work, duration, and assignment units and have a chance of sorting it all out.

    I hope this helps.

    Julie

    Thursday, June 7, 2012 12:46 PM
    Moderator