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Critical tasks ?

8 replies [Last post]
Bertrand GUERARD
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Hi !

Why tasks with duration in "edays" are not critial when predecesor and successor are ?

thks

Replies

Se de Leon
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I don’t understand why it shouldn’t work. this is the explanation.

1 day is calculated as 8 hours per day depending on what you assigned in the hours per day. elapsed days has 24 hours(3 days as calculated using 8 hours per day), that’s why in a critical path, task with elapsed days will have around 2 days slack always(about 16 hours). It sounds weird, but that’s how MSP is calculating the slack. Try it with only 4 tasks, you will see what I mean.

Or maybe you’re right. It’s possible they haven’t addressed this issue for MSP 2002.
Bertrand GUERARD
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yes, with 3 days too, but my tasks with elapsed durations are still not critical.

I think it is a bug in MSP-2002, a friend has tried on MSP-2007 and it seams to work.


Se de Leon
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have you tried it?
Bertrand GUERARD
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any change with 2 days.
Se de Leon
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Hi Bertrand,

Try 2 days for your slack threshold. We’ll discuss later why it should be 2 days not 1 day.

I hope this helps.

Se
Darren Kosa
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Hi Bertrand

Difficult question as I don’t know how many tasks you have that are ‘elapsed’

I have had a similar problems in the past and kept coming across this glitch, so I don’t use edays anymore.

If I know that I’m going to have to use elapsed time in a schedule, then I create a copy of the Standard Calendar and call it something like Elapsed Calendar, remove all the public holidays and make all the weekends non-default working time.

Then using the Gantt Chart view I insert the Task Calendar column and every task that would have had to use edays, I change the calendar from None to Elapsed Calendar and use normal duration to get the correct Start / Finish dates.

Because it uses a copy of the Standard Calendar and the working times are now 0900 – 1700, then the new created elapsed tasks should show as critical.

Hopefully this makes sense and you can use this method too.

Regards,

Darren
Bertrand GUERARD
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Hi Darren,

You are right.

Task1 (days) Start 8:00 Finish 17:00 Critical
Task2 (edays) Start 17:00 Finish 17:00 No Critical
Task3 (days) Start 8:00 Finish 17:00 Critical

What can I do ? I have lots of elapsed duration.

In Tools>Options>Calculation I use "Tasks are critical if slack is less than or equal to 1 days". But seams doesn’t work.






Darren Kosa
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Hi Bertrand

It probably has to do with edays using a 24hr calendar and your normal tasks using a standard calendar.

As a simple example, if you have 3 tasks with the 2nd task using elapsed duration.

The 1st task will start at 0900 and finish at 1700 as per the standard calendar.

The 2nd task will start at 1700 and finish at 1700 but on a different calendar.

The 3nd Task will then start at 0900 but back on the standard calendar, so MS Project thinks there is float and hence it won’t show critical.

I believe this is what you’re experiencing, but it’s easier to see if you have time showing on your Start and Finish columns.

Have a look Tools > Options > View and then change the date format to include time.

Regards,

Darren