HKSM
Start-to-Start (SS)
A dependency where the successor activity cannot begin until the predecessor activity has begun.
Key Points
- The successor may not start until the predecessor has at least started.
- Once the predecessor starts, both activities can proceed in parallel.
- You can add lead or lag to shift the successor's start relative to the predecessor's start.
- Controls start times only; it does not determine when either activity finishes.
Example
In a software project, begin integration testing 2 days after development starts. This is an SS relationship with a 2-day lag.
PMP Example Question
Activity B can start only after Activity A has started, and both may run concurrently. What dependency is this?
- Finish-to-Start (FS)
- Start-to-Start (SS)
- Finish-to-Finish (FF)
- Start-to-Finish (SF)
Correct Answer: B — Start-to-start relationship (SS)
Explanation: SS ties the start of the successor to the start of the predecessor; the successor cannot begin until the predecessor has begun.
