Project total negative float is less (in absolut value) than some activities' negative float

Hi everyone,

I'm using P3 and have a 4500 activities schedule. The problem I'm facing is the following:

The total float of the last activitiy of the project is -10 days, and I have within the program activities with -15 days of total float. I thought that the total float of the project should be at least the same as the lower total float of the activities (so the last activity of the project should show -15 days of total float).

I really don't understand how is this happening and how to solve it, i would appreciate some help.

¡Thanks!

Z
Zoltan Palffy 👤 Member for 16 years 10 months

have you set a project must fininsh by date ?

check this and make it the same as the constraint date on your last activity.

O
oriol manich 👤 Member for 14 years 10 months

Gary, 

Apart from the constraints, what I had was 2 calendars: one with 5 working days a week and one with 7 working days a week. Activities with the 7-working days created a path with less float than the critical path due to the P3 counting 7 days per each week.

Solved!

Thanks for your help!

Regards, 

 

G
Gary Whitehead 👤 Member for 17 years 2 months

You have a constraint which is forcing some of your activties to have -15 day float.

 

Go to one of your activities with -15d float, and open the successors. trace the successor which has -15d float, and keep doing this unitl you find the activity with the constraint. remove the constraint and re-schedule.

 

In my opinion it is generally not a good idea to use constraints in your schedule. Especially if you do not understand the effect they have on float.

 

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