Monitoring Deadline Dates in Primavera P6 EPPM

Emily 

in your example what wouldn't you use a finish on or before date for the milestones ? Using a finish on date constraint can delay an early finish or accelerate a late finish to satisfy the imposed date.

I do not believe that is what you want here. 

Hi Zoltan,

What I was tyring to say is that the deadline is a contractual date that is a specific date, so we constrain it with a ‘finish on’ constraint.

We want to measure schedule progress in relation to the ‘contract completion date’. If we use a ‘finish on or before’ constraint on ‘contract completion date’ and the ‘project completion date’ tracks to come in 2-days early, as per the ‘finish on or before’ constraint, the total float of that activity would be zero, indicating it is on time when in reality it is 2-days early. If we use a ‘finish on’ constraint and the ‘project completion date’ tracks to come in 2-days early, as per the ‘finish on’ constraint, the total float of that activity would be 2-days, indicating that our ‘project completion date’ is on track to finish early, which is what we want to show.

Does this make sense?

yes that is correct I think you would want to know that you have 2 days of float.

NO all contractual milestones should be finish on or before. As a matter of fact a lot of times that is the way that the contract terms are written finish on or before a certain date or within X number of days after NTP or award. 

I have never seen one that say "FINISH ON"

As Finish on or before constraint make sure that late finish date of an activity is not later than the early date. If the early date is earlier than the late date then you have positive float if it is later then you have negative float.