Schedule baseline
A schedule baseline is a saved copy of the approved schedule, the dates a project committed to, that progress and forecasts are measured against. The gap between a baseline date and the current forecast is the schedule variance.
Without a baseline, a plan that has quietly slipped looks the same as one that was always meant to finish late. With one, every forecast date can be compared with what was promised.
Teams re-baseline when the scope or the agreed dates genuinely change, and keep the earlier baselines so the history of the changes stays visible.
Worked example
| Task | Duration | Depends on | Scheduled | Total float | After the delay |
|---|---|---|---|---|---|
| 1. Requirements | 5 days | None | Days 1 to 5 | 0 days | Unchanged |
| 2. Build | 15 days | 1 | Days 6 to 20 | 0 days | Days 6 to 24 |
| 3. Testing | 5 days | 2 | Days 21 to 25 | 0 days | Days 25 to 29 |
| 4. Go-live | Milestone | 3 | Day 26 | 0 days | Day 30 |
The delay: Build takes 4 days longer.
The baseline has Go-live on day 26. After a slip of 4 days on Build, the forecast is day 30: a schedule variance of 4 days late.
Open this example in the free delay simulator to change the durations, the links or the delay and watch the schedule move.