Sizing, estimating and splitting user stories for sprints
Key Takeaway
Rank and schedule stories with the rough size estimates you already have. Add detail to the highest-priority stories as they near a sprint, instead of estimating every story precisely up front. If a large story has widely varying estimates and is needed soon, split it during backlog refinement into smaller, independent stories.
Before a user story goes into a sprint, the team needs to know three things about it: how it ranks against other work, whether it overlaps with other stories, and roughly how big it is. Scrum handles these with an ordered product backlog, regular refinement that breaks work into smaller chunks, and sprint planning, where the team commits only to the top items it can finish. The INVEST checklist is a quick test of whether a story is ready to estimate and schedule.
The product backlog and backlog refinement
The product backlog holds project work plus support or maintenance work, nonfunctional requirements and research. The product owner owns the product backlog and decides the priority of each item.
Backlog refinement happens every 2 weeks. The team looks a couple of sprints ahead, so the highest-priority items are ready to work on. During refinement, the team does three things:
- Breaks work into smaller chunks.
- Drafts conditions of satisfaction to clarify the desired outcome.
- Identifies work that is not ready.
The team refines the backlog continually as it learns. A user story can be refined as many times as needed.