Predecessor rules of precedence?

[G Lykos]

Greetings! Have been experimenting with various combinations of FS, SF, SS,
and FF predecessors relationships including varying lead/lags along with
Constraint Type near the project start date to try to understand who wins
when a task is pushed in different directions by multiple predecessors under
various scenarios. It would appear that a FS relationship is generally
strongest. Is anyone aware of an explanation (preferably on-line) of the
rules of precedence that MSP follows when resolving the net effect of
multiple predecessors? Not looking at leveling here - just basic
predecessor relationships and responses. Also, has the algorithm been
constant over MSP 98 SR-1 through current version?

Thanks,
George

 

[Dave]

Greetings! Have been experimenting with various combinations of FS, SF, SS,
and FF predecessors relationships including varying lead/lags along with
Constraint Type near the project start date to try to understand who wins
when a task is pushed in different directions by multiple predecessors under
various scenarios. It would appear that a FS relationship is generally
strongest. Is anyone aware of an explanation (preferably on-line) of the
rules of precedence that MSP follows when resolving the net effect of
multiple predecessors? Not looking at leveling here - just basic
predecessor relationships and responses. Also, has the algorithm been
constant over MSP 98 SR-1 through current version?

Thanks,
George

It's not really a question of precedence, rather a good understanding of
what they actually mean. None of the links mean that an activity will
start/end at the boundary of the previous task.

FS means that the linked task MAY but does not have to start when the
predecessor completes.

FF means that the linked task CANNOT finish before the predecessor task
finished but may do so some time later.

SS means that the linked task CANNOT start before the predecessor starts
but can do so some time later

SF means the linked task CANNOT finish before the predecessor task
starts but can do so some time later.

Hope this helps and apologies if I am teaching you to suck eggs. It is
important to understand that these link types don't dictate when
activities can occur, rather what has to happen before then can occur.

Dave