Setting lead AND lag time?

[Michael]

I want task B to start a week after task A starts, and end a week after task
A ends. It seems like I need to set both a lead and a lag time. Is this
possible, or is there some other way to accomplish this? I'm using 2007 Pro.
Thanks.

 

[Michael]

Further searching on this board lead me to "hammock tasks." I'll pursue that
further.

 

[Dave]

Further searching on this board lead me to "hammock tasks." I'll pursue that
further.

:

Create 2 milestones. Link the first SS to task A with a lag of 1 week
and the second FS to task A with a lag of 1 week. Then using copy/paste
special/paste link copy the milestone dates to the dates for task B.

 

[Steve House]

Links don't set the date where a successor task WILL start or end, they set
the earliest date the successor task is ALLOWED to start or end. They don't
fix the successor's schedule, they just set some boundaries for it. Setting
both a lag time and a lead time is impossible because they are mutually
exclusive. A lag time says the task begins later than the link says it is
permitted to start while a lead time says it begins earlier. A lag slips
the successor to the right while a lead pushes it to the left. How could
the your Task B move both to the right and to the left on the timeline at
the same time? Here's something to try, though. If B start a week after A
starts and ends a week after A ends, doesn't that mean that A and B have the
same duration but their running dates should be offset by one week? So set
it up this way ... Enter task A with duration X. Enter task B. Link A to B
Start-Start with a one week lag. Now select the duration of A and click
Edit/Copy. Select the duration of B and click
Edit/PasteSpecial/PasteLink/TextData. This will link the durations together
with B driven by A similar to the way a hammock task links start and end
dates and anything that forces a change in duration to A will force a
similar change in duration to B. This works, but be very, very careful
using it though. Tasks in a proper WBS are ALWAYS observable physical
activities and their durations are usually driven by the length of time it
takes to physically create the deliverable that the task produces - this
technique says that B's duration will always equal A's no matter what and I
can't see that as being an accurate model of reality very often. Think
about it like this - Task A is Paint North Wall and task B is Paint South
Wall. Since the walls are the same square footage, you'd expect it to take
the same length of time to paint each one. But does that mean it is locked
in granite that it actually WILL take the same length of time once you do
the work? Not likely. So you'd be better off forgetting about when B
finishes in relation to A's finish, instead just linking them SS with a 1
week lag time, and estmate each of their durations independently based on
how long you think it will take to finish whatever it is each task does once
it begins.

HTH

 

[davegb]

Links don't set the date where a successor task WILL start or end, they set
the earliest date the successor task is ALLOWED to start or end. They don't
fix the successor's schedule, they just set some boundaries for it. Setting
both a lag time and a lead time is impossible because they are mutually
exclusive. A lag time says the task begins later than the link says it is
permitted to start while a lead time says it begins earlier. A lag slips
the successor to the right while a lead pushes it to the left. How could
the your Task B move both to the right and to the left on the timeline at
the same time? Here's something to try, though. If B start a week after A
starts and ends a week after A ends, doesn't that mean that A and B have the
same duration but their running dates should be offset by one week? So set
it up this way ... Enter task A with duration X. Enter task B. Link A to B
Start-Start with a one week lag. Now select the duration of A and click
Edit/Copy. Select the duration of B and click
Edit/PasteSpecial/PasteLink/TextData. This will link the durations together
with B driven by A similar to the way a hammock task links start and end
dates and anything that forces a change in duration to A will force a
similar change in duration to B. This works, but be very, very careful
using it though. Tasks in a proper WBS are ALWAYS observable physical
activities and their durations are usually driven by the length of time it
takes to physically create the deliverable that the task produces - this
technique says that B's duration will always equal A's no matter what and I
can't see that as being an accurate model of reality very often. Think
about it like this - Task A is Paint North Wall and task B is Paint South
Wall. Since the walls are the same square footage, you'd expect it to take
the same length of time to paint each one. But does that mean it is locked
in granite that it actually WILL take the same length of time once you do
the work? Not likely. So you'd be better off forgetting about when B
finishes in relation to A's finish, instead just linking them SS with a 1
week lag time, and estmate each of their durations independently based on
how long you think it will take to finish whatever it is each task does once
it begins.

HTH

Re-read his post, Steve!

 

[Steve House]

Where did I miss what he said? Quote "I need task B to start 1 week after
task A starts and end a week after task A ends." Doesn't that imply that
the duration of A and B are equal? If the durations weren't equal and B's
start was offset from A by 1 week, the ends would be offset by some amount
other than 1 week would they not? He also says it appears he needs both a
lag time and a lead time and asks if it is possible. But even asking the
question betrays confusion of just exactly how links work and what lag times
and lead times are in the first place. I explained why it was impossible to
set both lag and lead into the relationship between two tasks at the same
time, provided a work around that would accomplish the scenario he said he
needed, and at the same offered a discussion why he should re-think the
approach he's taking since (IMHO) it's likely to lead to bogus, or at the
very least unrealistic, scheduling in the long run. Just where do you take
exception to that?

 

[davegb]

Where did I miss what he said? Quote "I need task B to start 1 week after
task A starts and end a week after task A ends." Doesn't that imply that
the duration of A and B are equal? If the durations weren't equal and B's
start was offset from A by 1 week, the ends would be offset by some amount
other than 1 week would they not? He also says it appears he needs both a
lag time and a lead time and asks if it is possible. But even asking the
question betrays confusion of just exactly how links work and what lag times
and lead times are in the first place. I explained why it was impossible to
set both lag and lead into the relationship between two tasks at the same
time, provided a work around that would accomplish the scenario he said he
needed, and at the same offered a discussion why he should re-think the
approach he's taking since (IMHO) it's likely to lead to bogus, or at the
very least unrealistic, scheduling in the long run. Just where do you take
exception to that?
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visithttp://www.mvps.org/project/faqs.htmfor the FAQs

Re-read his post, Steve!

- Show quoted text -

He can use a calculated field to calculate one of the dates, then use
a lead/lag to get the other. Kind of like a hammock task except it
involves a little more work to get the dates right. I call it a
"shadow task" because it's duration depends on the duration of another
task. Like writing code and testing it. When I saw he hit on hammock
tasks, I deferred answering because I knew he was on the right tack.