Calibrating Story Points Over Time: Prevent Estimation Drift
Team baseline drifts without realizing. 5-point story from 6 months ago now estimated at 3. Velocity looks like it improved—but estimates just deflated.
Quarterly Calibration Ritual
- Pull reference stories from 6 months ago
- Re-estimate them blind (don't show original estimates)
- Compare: Did estimates drift up or down?
- Discuss: Why? Team skill improved? Or baseline shifted?
- Update reference stories if drift confirmed
Signs of Drift
- Velocity steadily increasing with same team
- Velocity steadily decreasing with same team
- New team members say "that's not a 5, that's a 3"