Project: Actual Work in Task Table May Change Unexpectedly
  
PSS ID Number: Q111280
Article last modified on 10-14-1994
 
3.00 3.00a
 
WINDOWS
 

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The information in this article applies to:
 
 - Microsoft Project for Windows, versions 3.0, 3.0a
 - Microsoft Project for Macintosh, version 3.0
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SYMPTOMS
========
 
When you enter actual work in a task table, Microsoft Project may change
the entered value.
 
CAUSE
======
 
This behavior occurs as a result of the way Microsoft Project calculates
actual work on a task table when resources are assigned.
 
Microsoft Project calculates actual work with the following formula:
 
   Actual Work = (Task Work/Sum(All Resource Units))xResource Units
 
MORE INFORMATION
================
 
Steps to Reproduce Behavior
---------------------------
 
1. Use a dual-pane view with a task sheet on top, and a task form on the
   bottom.
 
2. With the task sheet active, choose Work from the Table menu.
 
3. Enter a task with a duration of 8h, and assign 1 unit of a resource to
   the task.
 
4. Change the resource units to .86.
 
The Duration should now be 1.16d, and work should be 8h.
 
5. On the task sheet, enter 8h in the Actual Work field.
 
The actual work will be recalculated to 7.98h.
 
Explanation
-----------
 
Microsoft Project calculates actual work with the following formula:
 
   Actual Work = (Task Work/Sum(All Resource Units))xResource Units
   (in this case Actual Work=(8h/.86)x.86)
 
Because Microsoft Project stores 8h as 480 minutes, 480/.86 = 558.1395.
Microsoft Project rounds the 558.1395 to 558 x .86=479.88, which is then
rounded to 479. Microsoft Project then converts this value back to hours as
479/60 = 7.9833, which is rounded to 7.98.
 
KBCategory: kbusage
KBSubcategory:
 
Additional reference words: 3.00 3.00a
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Copyright Microsoft Corporation 1994.
