We estimate effort in order to derive duration. The stakeholders always want to know “how long is this going to take?”.
What a Product Owner needs to know:
- Estimates should be provided by the production team
- Estimates should be created by the team as a whole and not by the most senior developer
- You need estimates before you can prioritize
- Estimates are not commitments
- Every estimate should come with a probability
- Estimates should be of relative, rather than absolute, size
Basic Principles
- Three (3) levels of precision
- Story estimates
- Task estimates
- Task remaining work
- Relative (unit-less) estimates on story level and above
- Hour estimates on task level
- Estimating is a collaborative effort performed by the whole team (e.g. facilitated by using planning poker or t-shirt sizing)
- Estimates are not commitments
Estimates are Always Accurate, Sometimes Right
Plans must always be accurate, but gain precision over time:
- ”We’ll be done between March and May.”
- ”We’ll be done sometime in April.”
- ”We’ll be done on April 24th.”
- Similarly, the business may not be able to accurately predict next years’ sales
