Setting a task xx weeks before a milestone

[ks]

I have no idea how to search for "how to"s on this one!

I have a milestone event, and want to create a simple dependency - "start
task y 9 weeks before the milestone" - if I change the date of the milestone,
task y should move forward or back to accommodate.

It seems crazy that this couldn't be done, but I can't seem to do it.

Help? Thanks!

 

[JulieS]

Hello ks,

Create a start to start link with 9 weeks lead. Once you've created
the link with the milestone as the predecessor, double click on the
link line -- change the link type to Start and Start and enter
-9w in the lag field.

I hope this helps. Let us know how you get along.

Julie
Project MVP

Visit http://project.mvps.org/ for the FAQs and additional
information about Microsoft Project

 

[ks]

Julie, you lovely human being. That's just what I was looking for - THANK YOU!

 

[JulieS]

Thank you for the enthusiastic feedback.

You are most welcome.

Julie

 

[Jim Aksel]

Some food for thought. Although we do what Julie has suggested almost daily,
there is more to think about. By establishing negative lag (lead) between
two tasks, you are essentually guaranteeing a future event. Unfortunately,
there is probably no better (aka "easier") way to do it.

That is once "A" kicks off with SS to milestone "B" the mere starting of the
predecessor then guarantees that "B" will occurr 9 weeks later. The world is
not that certain. It would probably be best to also have other logic that
drives "B" ... there must be something going on duration that 9 week time
that could cause "B" to be slip. Once you add that type of additional logic,
your schedule should be much more sound.
--
If this post was helpful, please consider rating it.

Jim Aksel, MVP

Check out my blog for more information:
http://www.msprojectblog.com

 

[DavidC]

Hi,

Have read both replies, and would add the following as another option.

Since the finish of one task is dependant on the start of another then try
the start to finish link. That then drives the activity 'back' off the
determining activity.

It is a very common requirement to have an approval or submission to be
completed a period of time before a construction type activity starts. Since
the construction activity shoudl not be held up by failure to meet the
submission date, I set the date as a milestone which in turn is used
dynamically to set the deadline on the work required to fulfill the activity
needing to be completed first.

An example is a commissioning plan needing to be submitted 9 weeks before
the start of commissioning. Setting the date for the submission as a start
to finish link, then sets the date by which the commissioning document needs
to be completed by. Using the ability to dynamically link dates using the
"Paste special" feature to set the deadline on development of the
commuissioning plan means that the it is now dynamic, and should the
commissioning look like starting earlier, will then set a new deadline.

Hope this helps.

REgards

DavidC

 

[Dytham]

Some interesting ideas there David. It's probably just me being thick, but in
your example, I can't get my head around how your start of commissioning
drives the submission date 9 weeks earlier.

I had also been looking at how to structure such events: ie. the
implementation is preceded by its final authorisation at a meeting 5 days
earlier, and wanted to avoid both negative lag and Finish No Later Thans. (Of
course if implementation moves, I would want to see the meeting date move
dynamically)

 

[Steve House]

Another thought ... while the milestone OUGHT to occur on a certain date,
there's no guarantee that it WILL occur on that date. The milestone itself
is an event, a change of state, ie, the contract changes state from "not
signed" into "signed." This state change occurs whenever its driving tasks
make it happen and it's possible that could be on, before, or after the date
you need it to be. To model the date this should occur, you should use the
Deadline field but do not attempt to fix the date. Instead, let Project
freely calculate where it will fall, based on predecssors etc, so you'll
know if the management decisions you are making are actually going to create
a project plan that is workable and meets your objectives. If Project
predicts you'll be a month late hitting your milestone, you can't just fudge
it by using a constraint to place the milestone where you want it - you have
to make some concrete change to the factors that are driving the event to
make it possible for it to hit the date you need.

 

[DavidC]

Hi Dytham,

One case would be contractual. The principal requires that a commissioning
plan is submitted no later than 9 weeks before the start of commissioning.
The start of commissioning may change as construction changes. It may arrive
earlier than originally planned or iot may come later. Either way the
contractor needs to ensure that the plan is submitted before that deadline.
So the logic is, the finish of the commissioning plan must occur 9 weeks
before the start of commissioning. Thios translates as "Commissioning plan
completed" has a predecessor of "Commissioning" with a SF -9wks link. Now
as the date of commissioning changes with construction so the date by which
the plan needs to be completed changes. The trick then is to make sure that
this becomes a critical activity, (you don't want to risk delaying the
contract by not submitting in time) so a deadline needs to be set on the
"commissioning plan completed" activity. Without a deadline and since this
method does not have a successor, it would have a large total float value.
To set a dynamic deadline, copy the finish date and then paste it using the
paste special Link, option into the deadline field.

Normally we think that every activity 'drives' a subsequent activity, but
documentation is often not the prime driver but a precondition to starting
the next activity but is not the driver for the activity. That means that if
the documentation is not furnished in time then there is a risk that the
activity (commissioning for example) may not be allowed to commence. If you
set a normal sequence and have the documentation as one of the drivers for
commissioning, you will see that the documentation does not need to be
started for a period of time out and delay starting. Then if construction
progress goes better and commissioning could start earlier, it is not always
that obvious that the plan needs to start or should have started.

I feel it comes down to the difference between one activity 'driving'
another and one activity being a contractual precondtion. I suggest that the
precondition date is driven by the activity that it is a precondition for.

For the example you have raised, I believe this process works well. The
driver for the meeting date is the expected comepletion date. Since the
completion date may change then so will the meeting date because of the
completion date, and not the other way around.

You do need though, negative lag since you need to tell the activity it
needs to finish a fixed period of time before the start of the driver
activity.

What I do is set the date for the activity as a milestone using it's own
finish date, and link the actual activity of work having a duration as a
standard FS link to the milestone. That way if the milestone overruns the
deadline, you have time to review the start or duration of the work activity.

Hope this helps and hasn't confused you further.

Regards
DavidC

 

[Paul Billings]

While using a SF-x link will back up a "dependent" activity to occur
at the correct time, combined with a hard link (PasteSpecial|Link) in
the deadline field of that dependent activity (to give a correct value
for slack) will "work", I have to question the logic in most
situations.

The cases that I've come across, the actual driving is actually the
other way. Consider some implementation task, followed by a review
meeting to discuss that implementation. The review needs a briefing,
and it must be sent to the customer 1 wk prior. Does the review
"drive" the briefing preparation or does the implementation&briefing
drive the review?

DavidC suggests that the review date drives the briefing preparation.
This is true only if the briefing will happen regardless. In my
experience, if I don't get the briefing prepared in time, the meeting
HAS to slip. I structure these events with normal FS links:
implementation->briefing prep->review (1 wk LAG). If I want to
emphasize (explain) the week delay, I will even put in a specific task
for it: imp->briefing prep->customer prep->review (no lags in any
tasks).

Paul

 

[Paul Billings]

While using a SF-x link will back up a "dependent" activity to occur
at the correct time, combined with a hard link (PasteSpecial|Link) in
the deadline field of that dependent activity (to give a correct value
for slack) will "work", I have to question the logic in most
situations.

The cases that I've come across, the actual driving is actually the
other way. Consider some implementation task, followed by a review
meeting to discuss that implementation. The review needs a briefing,
and it must be sent to the customer 1 wk prior. Does the review
"drive" the briefing preparation or does the implementation&briefing
drive the review?

DavidC suggests that the review date drives the briefing preparation.
This is true only if the briefing will happen regardless. In my
experience, if I don't get the briefing prepared in time, the meeting
HAS to slip. I structure these events with normal FS links:
implementation->briefing prep->review (1 wk LAG). If I want to
emphasize (explain) the week delay, I will even put in a specific task
for it: imp->briefing prep->customer prep->review (no lags in any
tasks).

Paul