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Negative Float

5 replies [Last post]
Mon, 2007-01-08 08:08
Alan Muir
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Hello,
I’m a new member and this is my first post, hope it’s successful.

Can anyone list all possible causes of negative float in a P3e plan?
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Replies

Thu, 2007-01-11 02:32
#1
Brennan Westworth
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Late start or finish constraints can also cause negative float when the activity logic and durations push past this date.

Negative float = early dates > late dates
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Wed, 2007-01-10 10:39
#2
Alan Muir
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Cheers Neil,

You were right on both counts. I appreciate your time & help with this problem.

Thanks,

Alan
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Wed, 2007-01-10 06:36
#3
Neil Branigan
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Dear Alan,

You probably have figured this one out already.

Must finish contraints are the root cause of this in my experience. In particular, at a project level in Primavera (P3e) you may place a project ’must finish by’ contraint. This will impact everything as soon as you start progressing your plan.

Another cause of this is when you have "loose logic". Your plan should input/output logic links except for the 1st and last activity! Loose logic causes havoc with your float calculations. However, it mainly gives you huge float values on certain activities as opposed to -ve float.

Cheers
Neil.
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Mon, 2007-01-08 12:15
#4
Alan Muir
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Thanks Charlie,

In my research on other sites/forums today I came across a similar sentiment & am now in the process of reviewing all constraints. This seems to be doing the trick. Thank you for confirming that I’m on the right track. Your help & your time are appreciated.

Alan
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Mon, 2007-01-08 12:12
#5
Charleston-Joseph...
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Hi Muir,

There is a big chance the schedule was constraint using "must be finish" dates.

Charlie
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