Best Practice for Using lags

[Alone]

Is there a best practice for using lags in schedules? I've just been told
not to use a lag from the beginning of a schedule to an activity a month down
the road. I used an FS+20d successor.

Is there a better way to show this relationship?

Thanks in advance,

Alone

 

[Rob Schneider]

Don't see anything wrong with what you are doing (Finish to Start with
20 day lag). If that correctly models the logic, what's wrong with
that? Did the person who told you "not to use a lag from the beginning
of a schedule..." tell you what's wrong with that approach?

 

[Gérard Ducouret]

Hello Alone,
There is not *a* best practice for using lags in schedule.
What you'll have to do, with all the available combinations of links and
lags, is to transcribe, the nearest as possible, the real world in your
schedule. You'll transcribe all the knowledge you have about your job.
How the predecessor governs its successor ? Is it the Start of the
predecessor which governs the Start of its successor with a waiting time of
3 days: SS+3d link...

Gérard Ducouret

 

[Alone]

Rob,

So far, the only thing I've found is that my boss does not like to use lags
like I described.

Thanks for the response,

Jim

 

[Alone]

Gerard,

Thank you for your insight. I appreciate your help.

Alone

 

[Steve House [Project MVP]]

Lags mean that there will always be the stated gap between the prdecessor
and the successor. With a lag, if the predecessor is delayed, the successor
will also. Whether one should use lags or not depends on whether they
describe an accurate model of the real behavior. If I mail out a survey and
need to allow two weeks for the responses to come back, that two week delay
will hold true regardless of whether I mail that survey today or next week
and so using a lag in the link between "mail survey" and "analyze responses"
would be perfectly appropriate. OTOH, if I finish a task next week but
can't start its successor task until January because that when the parts I
need will be delivered, then a lag is not the most accurate way to represent
that reality. If I finish the task in two weeks, it can still start in
January. If I finish in three weeks, I can still start on the same day in
January,. Only if I delay the predecessor so that it itself doesn't finish
until January will I need to delay its successor. In that case, instead of
a 6 week lag in the link, a simple FS link with a Start No Earlier Than
constraint on the successor task is a more accurate model of what's really
happening.

 

[Alone]

Steve,

Thanks for the very informative reply and the time you took to provide it.

Sincerely,

Alone