Start-to-Finish (SF)

Start-to-Finish is the least common logic tie in CPM scheduling and is generally recommended to be used sparingly, if at all. In an SF relationship, the successor activity cannot finish until the predecessor activity has started. This relationship is somewhat counterintuitive because it links the start of one task to the finish of another, which makes it less intuitive than FS, FF, or SS. Most project activities are better modeled with the other three relationship types, and SF should only be applied when no other relationship accurately represents the workflow.

Proper use of SF can help capture unique scheduling scenarios, such as shift transitions or handover tasks, but misuse can create confusion and misrepresent the project logic.

Example: Night-shift cleanup of a construction site (successor) cannot finish until the day crew (predecessor) begins their work. This ensures that the night crew completes their tasks only when the day crew is ready to take over, maintaining continuity and safety on the site.