Why is Project calculating durations incorrectly?

[Chris - FidelityFlight]

I have a task that is 15 days in duration. The task is 8 days complete and
has a remaining duration of 7 days. The task started on Aug 26.

When I update the task with the actual start of Aug 26 and an actual
duration of 8 days, Project calculates the remaining duration of 7 days.
That is good. However, it pushes the finish date to Sept 23rd. That would
make the duration to be 20 days.

I tried something else to see what would happen. I updated the task to show
an actual start of Aug 26 and an actual finish of Sept 16. That should be a
15 day duration. However, Project calculates it to be only a 10 day
duration.

The task is not constrained by any parameters, and has only one predecessor
and one successor that are simple FS relationships. The task is not critical
either.

What is going wrong? I want the durations to reflect a real number so I can
use the info for historical data. This isn't the first time I have had this
happen either.

 

[John]

"Chris - FidelityFlight" <Chris -

I have a task that is 15 days in duration. The task is 8 days complete and
has a remaining duration of 7 days. The task started on Aug 26.

When I update the task with the actual start of Aug 26 and an actual
duration of 8 days, Project calculates the remaining duration of 7 days.
That is good. However, it pushes the finish date to Sept 23rd. That would
make the duration to be 20 days.

I tried something else to see what would happen. I updated the task to show
an actual start of Aug 26 and an actual finish of Sept 16. That should be a
15 day duration. However, Project calculates it to be only a 10 day
duration.

The task is not constrained by any parameters, and has only one predecessor
and one successor that are simple FS relationships. The task is not critical
either.

What is going wrong? I want the durations to reflect a real number so I can
use the info for historical data. This isn't the first time I have had this
happen either.

Chris,
I tried you scenario on a test file and of course everything works fine
for me. However, you scenario begs some questions.
1. Are you using working time duration or elapsed duration?
2. Are you using a standard calendar (i.e. 8 hour days, 5 day week)?
3. Does your calendar have Monday, Sept 5 as a holiday?
4. Are there any resources applied to the task?
5. If there are resources, does the resource use the default task
calendar or does the resource have its own calendar?
6. Was the task leveled?

By the way, Aug 26 through Sept 16 is 16 working days, not 15.

Hope this helps.
John
Project MVP

 

[Chris - FidelityFlight]

Thanks John,

1. I am using the work time durations with a standard calendar.
3. Not sure about the holiday (but I was missing 5 days - not just one).
4. Resources are applied and use the default calendar
6. I don't know about levels - so I don't know if it was or not.

Not sure what to think. In the beginning I figured I would shutdown Project
to see if that might be the problem. I tried a couple times and the problem
persisted. Thats when I posted the question.

I shutdown again during lunch. When I returned, the problem went away. I
still find it interesting that it only did it with one task though, and not
the others that I uipdated.

 

[John]

"Chris - FidelityFlight"

Thanks John,

1. I am using the work time durations with a standard calendar.
3. Not sure about the holiday (but I was missing 5 days - not just one).
4. Resources are applied and use the default calendar
6. I don't know about levels - so I don't know if it was or not.

Not sure what to think. In the beginning I figured I would shutdown Project
to see if that might be the problem. I tried a couple times and the problem
persisted. Thats when I posted the question.

I shutdown again during lunch. When I returned, the problem went away. I
still find it interesting that it only did it with one task though, and not
the others that I uipdated.

Chris,
Well, everything sounds pretty generic (i.e. default). My last question
about leveling applies to a feature of Project found under
Tools/Resource Leveling. When leveling is activated, it initiates an
algorithm that allows Project to automatically move tasks around (i.e.
shift, delay, split, etc.) to relieve resource conflicts
(overallocation). The default setting is "manual" (i.e. no leveling) but
you might want to check to see if the setting was changed to
"automatic". In the absence of a pure poltergeist (e.g. corruption),
leveling might be germane to the problem you are seeing.

The fact that the problem seemed to "fix itself" while you were out to
lunch (no pun intended), suggests that file corruption may be present.
In that case, go to the MVP website at:
http://www.mvps.org/project/faqs.htm
and take a look at FAQ 43 - File Bloat? - Might be corruption

Hope this helps.
John
Project MVP

 

[Steve House [Project MVP]]

Remember any non-working times - Saturday, Sunday, evenings, or holidays -
do not count towards duration. If a task starts on 01 Sep 8am and ends on
30 Sept @ 5pm and the 5th is shown as a holiday in the working time
calendar, that task's duration is 21 days, not 30 days.