PRJ: How Percent Complete Is Calculated for Nested Summary Tasks

This article was previously published under Q101495
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Microsoft Project calculates the Summary Level Percent Complete valuebased on its immediate subordinate tasks (summary and detail tasks).This method of calculation can cause the percent complete for ahigher-level summary task to differ from a calculation done by hand ifonly the detail tasks and not the subordinate Summary tasks are used.

The Percent Complete for a Summary Task is a weighted average of itsimmediate subordinates.
In order for Microsoft Project to speed up calculations, the percentcomplete of a summary task is based on its direct subordinate tasksand subordinate summary tasks percent complete (if any).

Project uses the following calculation:
   Percent Complete = Actual Duration / Duration				
For a summary task, percent complete is first calculated from itsimmediate subordinates, and then actual duration is determined. For atask, either percent complete or actual duration can be solved.

The following example assumes a default base calendar with no resourceassignments:
   Name             Outline   Dur   Sch St   Sch Fin  %Comp   Act DurTop Summary           1       8d    1/1/96    1/10/96   23%    1.8dSubordinate Summary   1.1     5d    1/1/96    1/5/96    25%    1.25d   task1              1.1.1   1d    1/1/96    1/1/96    50%    0.5d   task2              1.1.2   1d    1/5/96    1/5/96     0%      0d task3                1.2     1d    1/10/96   1/10/96   10%    0.1d				
NOTE: In Microsoft Project 98/2000, the Percent Complete is 20% instead of 23%and Actual Duration is 1.6d instead of 1.8d.

Percent Complete of the "Subordinate Summary" is calculated like this:
   (1d*50%+1d*0%)/2d=25% [(task1 dur) * (task1 %Comp) + (task2 dur) *   (task2 %Comp)] / [(task1 dur) + (task2 dur)]				
Percent Complete of the "Top Summary" is calculated like this:
   (5d*25%+1d*10%)/6d=22.5% (=23%) [(Subordinate Summary dur) *   (Subordinate Summary %Comp) + (task3 dur) * (task3 %Comp)] /    [(Subordinate Summary dur) + (task3 dur)]				
Because the duration of the "Subordinate Summary" does not equal theduration of its subordinate tasks, the percent complete of the "TopSummary" task does not reflect the percent complete values of thetasks themselves.

If the Percent Complete of the "Top Summary" was based on only thesubordinate tasks, and not the "Subordinate Summary," it would becalculated as follows:
   (1d*50%+1d*0%+1d*10%)/3d=20% [(task1 dur) * (task1 %Comp) + (task2   dur) * (task2 %Comp) + (task3 dur) * (task3 %Comp)] / [(task1 dur)   + (task2 dur) + (task3 dur)]				
prj2000 3.00a %Complete % Complete

Article ID: 101495 - Last Review: 12/04/2015 09:33:49 - Revision: 3.1

Microsoft Project 2000 Standard Edition, Microsoft Project 98 Standard Edition, Microsoft Project 4.1 Standard Edition, Microsoft Project 4.1a, Microsoft Project 3.0 Standard Edition, Microsoft Project 3.0a, Microsoft Project 4.0 Standard Edition

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