Work hours and Duration don't add up correctly

[AmyD]

When I change the duration or work hours for a sub-task the hours for the
main task do not add up to what I have entered below. It will sometimes take
the highest number as its total rather than adding them all up. Or sometimes
it will take part of the sub-tasks and add them up rather than all sub-tasks.

What am I doing wrong? I can't edit the main task headings which is driving
me crazy. Is there not a way to edit those, when I go into the detail they
are gray and I cannot change it. If I could just manually enter the right
total it would help a lot.

Is this possible to manually change the main task durations and work hours?

 

[JulieS]

Hi AmyD,

The duration of a summary task is calculated as the amount of working time
(days, hours, weeks) from the start of the first of the subtasks to the
finish of the last of the subtasks. Because the duration is calculated, you
cannot change the duration of the summary tasks directly. If you change the
durations and links of the subtasks, the summary task duration will
recalculate.

Work is not the same as duration. Work is calculated by:
Task Duration * Resource assignment units = Work

For example: for a task with 1 day (8 hours) duration, if I assign 3
resources all at 100% units, the amount of work on the task is 24 hours. (3
people each working 8 hours but at the same time.)

You may want to take a look at Mike Glen's excellent series of articles at:

http://pubs.logicalexpressions.com/Pub0009/LPMFrame.asp?CMD=ArticleSearch&AUTH=23

Hope this helps. Let us know how you get along.

Julie

 

[JackD]

Duration is not the sum of work hours.
The summary task should show the total of the sub task WORK as long as the
summary task does not have any resources assigned to it. If it does then it
will be higher.
Duration of the summary task is calculated as the difference between the
start of the earliest sub task and the finish of the latest sub task. If the
two sub tasks are parallel and are one day each then the summary task will
have a duration of a day. If they are sequential then the summary task will
have a duration of two days. If there is a gap between them then the summary
task will be even longer than the sum of the two sub task durations.

--
-Jack ... For Microsoft Project information and macro examples visit
http://masamiki.com/project
or http://zo-d.com/blog/index.html
..

When I change the duration or work hours for a sub-task the hours for the
main task do not add up to what I have entered below. It will sometimes take
the highest number as its total rather than adding them all up. Or sometimes
it will take part of the sub-tasks and add them up rather than all sub-tasks.

What am I doing wrong? I can't edit the main task headings which is driving
me crazy. Is there not a way to edit those, when I go into the detail they
are gray and I cannot change it. If I could just manually enter the right
total it would help a lot.

Is this possible to manually change the main task durations and work

hours?