What happens if milestone 1 moves earlier or later in the schedule?
A link says that one event is controlling another, in your case the
occurance of Milestone M1 is purported to control the occurance of Milestone
M2. But I get very curious about the sort of logic you're trying to create
where an event is controlled by something in its future. According to your
example, M2 occurs 10 weeks before M1 or put another way 4 weeks after the
start of the sequence of events leading up to M1. But what would happen if
it turned out that there was an unexpected delay in that M1 sequence not
apparent until, say, weeks 8, 9, and 10 after it begins, a resource
unexpectedly goes on sick leave perhaps, so the work doesn't go as fast as
first anticipated and M1 gets pushed back three weeks. Since M1 is linked
to M2 and controls its date, that means M2 should also be delayed 3 weeks.
But M2 CAN'T be delayed because it's already happened and what happened,
happened when it happened >grin>. It seems more reasonable to think
something other than M1 controls when M2 can happen and M1 will happen at
least 10 weeks after whenever M2 happens, the control flowing so that M2 is
one of several factors that controls M1 rather then the way you've
postulated here. That's not to say you can't set up a link like you've
asked, I just wonder if it's really going to give you a valid predictive
model.
Another issue is that indicating when something SHOULD occur is the function
of a deadline entry, not a link. The deadline is how we indicate our
business objectives. A link, OTOH, computes when it WILL occur if we deploy
our assets in a certain way and that computed date could end up before, on,
or after the required deadline. The plan predicts what's going to happen if
we work in a certain way, the deadlines indicate what our business objects
require us to achieve. Then if the computed dates don't fall within their
deadlines, it's our job as scheduler to rearrange the work so to make it
possible for the former to fall within the latter.
To get M1 to control M2 so it occurs 10 weeks before M1, set the link
M1->M2, link type of Start-to-Finish (the reverse of the usual FS), and a
10-week lead time (negative 10w lag time)
