Lead
Lead is negative lag: it lets the successor start before the dependency would otherwise allow, so the two tasks overlap. It is used to fast-track work that can begin on a partial output.
Lead is written with a minus sign: 1FS-3 means start three days before task 1 finishes. A designer can start laying out pages while the last of the copy is still being written.
Lead shortens the schedule but adds risk: the successor starts on an unfinished input, so rework becomes more likely if that input changes.
Worked example
| Task | Duration | Depends on | Scheduled | Total float |
|---|---|---|---|---|
| 1. Write content | 10 days | None | Days 1 to 10 | 0 days |
| 2. Design layout | 5 days | 1FS-3 | Days 8 to 12 | 0 days |
Write content runs to day 10. With a lead of 3 days, Design layout starts on day 8 instead of day 11, and the two tasks overlap.
Open this example in the free delay simulator to change the durations, the links or the delay and watch the schedule move.