A question on "Using deadlines to create slack"

[JNB]

Hi all,

According to HA102118001033, the following is an exception to Late Finish =
Deadline condition;
if the late start minus the lag is earlier than the deadline for one of the
task's successors, the late finish equals that successor task's late start
minus the lag.

I would appreciate if you can give an example of a case that creates the above
condition.

Thanks for any feeedback.
Best Regards - JNB

 

[Jack Dahlgren MVP]

Two tasks A and B
A has a deadline of 31DEC2009
A starts 01JAN2009 and has duration of 2 weeks.
B is a successor to A and has a duration of 2 weeks.

The critical path through this project is clearly A-B and has a duration of
4 weeks
Late Start and Early Start, and Late Finish and Early Finish for critical
tasks are the same (Slack or Float = 0)

In this case, the deadline is far beyond the late start of B so it plays no
part in setting slack for task A

Now move the deadline to 02JAN2009

Slack for A is now negative.

So it is simple, slack is always driven in the traditional way, UNLESS the
deadline is earlier than the earliest late start dates (+ offset for lag -
which would apply in either case) for the successors.

-Jack Dahlgren

 

[JNB]

Thanks Jack.
---
Best Regards - JNB

Two tasks A and B
A has a deadline of 31DEC2009
A starts 01JAN2009 and has duration of 2 weeks.
B is a successor to A and has a duration of 2 weeks.

The critical path through this project is clearly A-B and has a duration of
4 weeks
Late Start and Early Start, and Late Finish and Early Finish for critical
tasks are the same (Slack or Float = 0)

In this case, the deadline is far beyond the late start of B so it plays no
part in setting slack for task A

Now move the deadline to 02JAN2009

Slack for A is now negative.

So it is simple, slack is always driven in the traditional way, UNLESS the
deadline is earlier than the earliest late start dates (+ offset for lag -
which would apply in either case) for the successors.

-Jack Dahlgren