Which task dependency is the rarest type of schedule relationship and involves the successor not being able to finish until the predecessor starts?

Which task dependency is the rarest type of schedule relationship and involves the successor not being able to finish until the predecessor starts?

• A. Start-to-Finish (SF)
• B. Finish-to-Start (FS)
• C. Finish-to-Finish (FF)
• D. Start-to-Start (SS)

Answer: (A)

Start-to-Finish is the rare schedule relationship where the finish of the successor is constrained by the start of the predecessor. In other words, the successor cannot be completed until the predecessor has begun. This is unusual because most project relationships link a task’s start or finish to the other task in a more intuitive way (for example, one task cannot start until another finishes, or cannot finish until another starts). An example helps: if the final testing task cannot be completed until the development task has started, that’s a Start-to-Finish constraint. Because this kind of constraint is counterintuitive and rarely needed in typical project sequences, it’s considered the rarest type.

Start-to-Finish is the rare schedule relationship where the finish of the successor is constrained by the start of the predecessor. In other words, the successor cannot be completed until the predecessor has begun. This is unusual because most project relationships link a task’s start or finish to the other task in a more intuitive way (for example, one task cannot start until another finishes, or cannot finish until another starts). An example helps: if the final testing task cannot be completed until the development task has started, that’s a Start-to-Finish constraint. Because this kind of constraint is counterintuitive and rarely needed in typical project sequences, it’s considered the rarest type.