How to Improve Estimation Accuracy Over Time
We've been doing scrum for a year but our estimates still suck. Stories we think are 3 points turn into 13, 8-pointers get done in a day. How do teams actually get better at this?
Retrospective on estimates, not just sprints. Last 15 minutes of retro: pull 3-5 completed stories, compare estimate vs actual effort. What did we miss? Hidden dependencies? Tech debt? Testing complexity?
Document patterns. After 6 months you'll have a 'estimation mistakes checklist' that catches 80% of misestimates before they happen.
Break stories down smaller. We instituted a hard '8 point max' rule. Anything bigger must be split. Smaller stories = less uncertainty = better estimates. Our accuracy went from 40% to 75% within 3 sprints just from this.
Track estimate vs actual in a spreadsheet. Calculate your team's 'fudge factor' - ours is 1.4x. If we estimate 20 points, we actually complete ~14. Now we plan accordingly and hit commitments. Not perfect but way better than pretending we'll magically get accurate.
The person who estimates should be the person who implements. We used to do team estimates but the senior dev always ended up doing it. Now only the dev who'll code it estimates. Forces ownership and estimates got 2x more accurate immediately.