Why Re-estimate User Stories? #scrum #agile #xp
On the SCRUM Development list two questions often pop up, I call them the why and when of re-estimating. There are few defined rules on re-estimating, yet estimating and re-estimating is an important part of backlog grooming. Which is why this is a recurring question in many SCRUM fora.
Why should we re-estimate user stories?
As time goes on ideas and opinions have the tendency to crystallize and become more clear in the mind’s eye. The same goes for User Stories in the backlog, our opinions on scope and complexity User Stories become more well defined. This may mean that a User Story needs to have its metrics re-evaluated and re-estimated.
- When something new is learned about the User Story
- When User Stories are merged stories or split up
- The relative sizes of the User Stories changed
- Uncertain about the complexity of the User Story
- The team believes the estimate for any future work needs to be re-discussed and/or re-estimated
When should we re-estimate user stories?
- If we re-estimate the stories, we it prior to the sprint, during a grooming session
- Check the estimates during sprint planning session
- Re-estimate any story that has not yet been accepted into a sprint
If we don’t re-estimate:
- The velocity will go through the roof when we implement those stories and the variations in velocity will be greater
- The release plan will be less realistic and the range of story points to release will vary widely
- We keep our estimates coherent with the past but less coherent for the future. New stories will be estimated as smaller even though relative sizes will be the same
If we re-estimate:
- We shall re-estimate all the workflow stories to keep them coherent
- The velocity will remain stable
- The release plan will be positively reviewed and allow us to take more in
- We make our estimates for the future more coherent if we add any new story
A discussion on Re-estimate User Stories for a More Accurate Velocity?
Sources: Stephan Huez, Roy Morien, Steve Ropa, Charles (chuckspublicprofile)