In Agile Scrum, user story estimation is the process of assessing the effort required to implement a user story. The goal is to help the team understand the relative complexity, risk, and size of each task so they can plan and prioritize effectively.
🛠️ Common Estimation Techniques
1. Story Points (most common)
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A relative measure of effort (not tied to hours or days).
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Typically use a Fibonacci sequence (1, 2, 3, 5, 8, 13, etc.) to reflect increasing uncertainty as complexity grows.
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Factors considered: complexity, risk, unknowns, amount of work.
2. Planning Poker
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Team members estimate a story by playing cards with point values.
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Everyone reveals their card at once, then discuss differences.
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Repeated until consensus is reached.
3. T-shirt Sizes
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Use sizes like XS, S, M, L, XL to indicate rough sizing.
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Often used in early backlog grooming or with non-technical stakeholders.
4. Bucket System
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Stories are sorted into "buckets" of effort (e.g., 1, 2, 3, 5, 8 points) through collaborative team discussion.
📦 Example User Story:
“As a user, I want to reset my password so that I can regain access if I forget it.”
Team might discuss:
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Is it a standard workflow?
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Any third-party integration (e.g., email)?
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Edge cases (token expiration, security)?
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Level of test coverage needed?
After discussion, team agrees it’s a 5-point story.
✅ Best Practices
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Estimate as a team, not individually.
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Keep estimates relative (compare stories against each other).
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Don’t equate story points directly to hours.
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Re-estimate if requirements change significantly.
