Finish-to-Start (FS)
A schedule dependency where a successor activity is allowed to begin only after its predecessor has been completed.
Key Points
- The most common relationship in precedence diagramming (PDM) schedules.
- Can include lag (a delay after finish) or lead (the successor starts slightly before the predecessor fully finishes).
- Influences sequencing, critical path determination, and float calculations.
- Shown in network diagrams as a link from the predecessor's finish to the successor's start (FS).
Example
In a construction project, "Frame walls" starts only after "Pour foundation" is complete; a 2-day lag may be added to allow the concrete to cure before framing begins.
PMP Example Question
Which relationship type applies if user training may begin only after the new system is fully deployed?
- Finish-to-Start (FS)
- Start-to-Start (SS)
- Finish-to-Finish (FF)
- Start-to-Finish (SF)
Correct Answer: A — Finish-to-Start
Explanation: Training (successor) cannot start until deployment (predecessor) is finished, which is an FS dependency.