I’m not sure if this is possible, but I thought I would give it a shot! I have a task (Perform Factory Acceptance Test (FAT)) whose start is contingent on a number of other tasks. I need to inform the customer of the date of the FAT 14 days prior to the start of the FAT. The FAT of course is contingent on completing the aforementioned tasks, but is also contingent on notifying the customer of the FAT, but I want to set the Notification date 14 days prior to the start of the FAT and do not wish to set a constraint date as the date will undoubtedly change depending on the actual completion dates of the pre-FAT tasks.
I think what you are trying to do is relatively simple.
You have a notification task that needs to occur 14 days prior to the Start of FAT task. This should accomplish that.
Set a successor relationship between Notification Task and Start of FAT task. In that relationship, set a Lag value of 14 days. Then in the Notification Task, set the task to schedule As Late As Possible.
The Notification task technically needs no predecessor.
In this scenario, if the Start of FAT task shifts in either direction, the Notification task will automatically adjust accordingly and because it’s As Late As Possible with a Lag of 14 days, the Notification task should always appear 14 days prior to the Start of FAT task.
Hope that helps
Thank you for the response, Daryl. The issue I run into when I follow your steps is that because I’ve set Notify Customer as ALAP, the task gets pushed back to the end of the project. Setting the lag up is fine – it spaces the tasks apart by 14 days. Because the Perform FAT has no predecessor, I can’t set a lag to that task.
I instead configured the Notify Customer as a predecessor to Perform FAT and set the lag on Notify Customer to -14 days. It kind of does what I want – the issue is that the Notify Customer task should technically be completed before the FAT is performed, though I can’t add in a lag if it does not have a predecessor. I’ve configured it as a milestone (zero duration) and as a Start-Finish relationship and it seems to be working.
In the absence of a true Zero-Free-Float milestone in MSP, I typically handle this with a ready-for-FAT milestone.
i.e. (predecessors in parentheses)
1 – All physical activities up to and concluding with the driving predecessor of FAT.
2 – Ready for FAT (1 FS)
3 – FAT Notification (2 FS-14d)
4 – FAT (2 FS, 3 FS)
If contract absolutely prohibits start of FAT until 14d after notification, then the “3 FS” becomes “3 FS+14d”.
Thank you for the suggestion. I will try it out.
Why not create the FAT notification task as predecessor of FAT with a negative lag?
1 FAT prep 15 days Mon 18 Sep Fri 06 Oct
2 FAT 1 day Mon 09 Oct Mon 09 Oct 1
3 FAT notification 0 days Tue 19 Sep Tue 19 Sep 2SS-14 days
A well-developed, logic-driven project schedule a) Reflects the technological and logical constraints between activities as accurately as possible; and b) Supports a valid forecast of the consequences when activities do not proceed as planned.
The essence of the logical statements under automatic scheduling is that the “Successor” shall be scheduled As Soon As Possible subject to the constraint that it May Not Start (or Finish) before its “Predecessor” has Finished (or Started) – (depending on the type of relationship, FS is assumed). Scheduling the Notification as a (SS-14) Successor of the FAT is stating that the Notification will be scheduled As Soon As Possible except that it May Not Start before (14 days before) the FAT Starts. Any circumstance that delays the Notification has no consequence for the FAT. The Early Start date may end up exactly where you want it, but the Late Start and Slack values would be incorrect.
If the contract prohibits carrying out the FAT without first notifying the customer, then the notification must be a predecessor of the FAT. The approach I suggested keeps the logic flowing in the right direction.
Your method works correctly. If you didn’t need to provide 14 days notification, the tasks would still be completed in the manner you suggested (perform everything up to performing the FAT, notify the customer that you will perform the FAT, perform the FAT). In my case, I simply need to inform them 14 days prior to the anticipated FAT date, which is exactly how you described it.
Thanks for the help.