How do I set up EXACT lead time

[jjbgames]

I am trying to keep all the dates relative so that I can use this as template
in the future. I have now hit a problem. Here is the situation:

assume 3 tasks. X,Y,Z. Z is the final that happens at a set date. I have
changed the project to schedule from end time. I can set X as a predecessor
of Z with a lag time of 25 days. This moves X to end time - 25
days(perfect). If I set Y to X+7, it leaves Y as the same time as Z because
all are set to as late as possible. If I change Y to be as early as
possible, it moves X back to the project start date to make Y start date +
7.

I want X to stay 25 days before Z and Y 7 days after that. Is there a way
to make lag and lead time be EXACTLY and not AT LEAST?

 

[Jan De Messemaeker]

Hi,
I'm afraid the answer is no, sorry :-(

 

[Steve House [MVP]]

Try this ... Z is the controlling task, right? So make it the predecessor
with X the successor in a SF relationship and add a 25 day lead time. This
will move the finish of X to 25 days before the start of Z. Now link X FS
as the predecessor to Y as its successor with a 7 day lag time.

That being said, you might wish to reconsider your strategy. Project is
best used to figure out when Z will occur IF X starts on a certain date. If
the start that you choose for X makes Z hit the target, well and good. If
it doesn't, you know you have to change the start of X. If you actually
schedule from Z backwards you will know the latest date X should start in
order for Z to hit ontime IF everything goes perfectly according to plan.
But the one thing you can count on in Project Management is that things
NEVER go 100% according to plan. By scheduling backwards from the required
date you have put all your eggs in one basket and the fates are not in your
favour that you'll actually be able to deliver. You're much better off
perhaps scheduling backwards to find out what the absolutely latest possible
date you could start X might be, but select a start date well ahead of that
and actually schedule the work from the start date forward with deadlines
set to monitor whether or not you're hitting your required completions.