Dependencies and lag

Dependencies

A dependency links two tasks so that scheduling one affects the other.

Dependency types

• FS (Finish-to-Start) — the successor starts when the predecessor finishes. The most common type.
• SS (Start-to-Start) — the successor starts when the predecessor starts.
• FF (Finish-to-Finish) — the successor finishes when the predecessor finishes.
• SF (Start-to-Finish) — the successor finishes when the predecessor starts.

Lag

Lag is a delay (in days) added after the predecessor before the successor can start. A lag of 2 means "wait 2 working days after the predecessor finishes."

Creating a dependency

1. Open a task → Details tab → linked tasks section, or
2. On the Timeline, drag from the right edge of one bar to another.

The critical path is calculated from your dependencies — it's the longest chain that determines the project finish date.