FF/SS with lag/lead and Forward/Backward Pass Calculation

[MikeY007]

Can anyone tell me how Project calculates earliest and latest dates (times) for the following cases? I have checked the Task 1 (predecessor) and Task 2 (successor) linked with Finish-to-Finish or Start-to-Start dependency with lag or lead time. I have also found a couple of CPM guide on the internet but they only contain examples of Finish-to-Start dependency. What is the reason for this thing? Thanks.

[Anywhere]

You can try to create two such tasks and look at the result.

[spookshow]

If you want for a SS link, then early start of the successor is larger than or equal to the Start of the predecessor plus the lag if any. For a SS link, Late start of the predecessor is less than or equal to the Start of the successor less the lag if any. For a FF link, Early finish of the successor is larger than or equal to the finish of the predecessor plus the lag if any. For a FF link, Late Finish of the predecessor is less than or equal to the finish of the successor less the lag if any.