Project will always try to get everything done as soon as possible. If you
could do it, you really would start everything on the project start date and
run them in parallel because that is what would get the job finished the
quickest but the real world is rarely so tidy and cooperative. There are
essentially three things that would make the tasks start at some time other
than the project start date.
The first as you have already discovered is a constraint. An example of the
proper application of this is we're starting the BigProject right after New
Years but one of the tasks requires parts that are on backorder and won't be
delivered until Feb 1st. Using a Start No Later Than constraint of 01 Feb
insures the task won't be scheduled to start before the required parts are
delivered.
The second reason you can't do a task on the project start date is that
something else in the project has to happen first. That's where links come
into play. You can't park a roof in mid-air defying gravity and later build
the supporting walls under it. Walls link to Roof FS to insure the walls
are scheduled to be built first.
The third reason you can't do all the tasks on the project start date is the
resources who will do the work aren't available. We have two tasks A and B
and when we first put them into the plan they're both starting 1 Jan. The
only guy on staff who has the skills to do them is Fred, but he's on
vacation the first 2 weeks of January. When we assign Fred to them both
tasks will move from 02 Jan to the first date he's back at work after
vacation, driven there by his resource calendar. But we're not quite done.
He's still scheduled to do both tasks at the same time and he can't be two
places at once. So we run resource leveling and one of those two tasks will
move on out to start after the first one has ended.
I tell my students not to worry that all the tasks show up initially on the
project start date. It will make sense once you get all the pieces to the
puzzle in place but not before then. If you already have some dates in mind
for tasks and Project is telling you something different, it most likely
means your initial ideas are unworkable
Regarding the fact that a constraint is always set when you enter start and
finish dates on tasks... Project's job IS NOT to document a schedule you
have already worked out. It works the opposite way. You don't tell it the
dates for tasks - it tells YOU. You tell it what has to be done and what
assets you have to do it with and it tells you when you're supposed to
schedule the tasks in order to get the project done as soon as possible.
IMHO the only reason you're allowed to input dates in the Start and Finish
columns at all is that it is a useful convenience to be able enter
constraints as you're working in the task list for those rare tasks that
need 'em. .
--
Steve House [MVP]
MS Project Trainer & Consultant
Visit
http://www.mvps.org/project/faqs.htm for the FAQs
