Agile in a Flash 23

Story Estimation Fundamentals – The Plan

Agile in a Flash by Jeff Langr and Tim Ottinger (card #23)

> All contributors estimate

> Break story into tasks to verify scope

> Come to Consensus with Planning Poker

> Decrease granularity as story size increases

> Estimate with relative sizes

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Estimates are always wrong—it’s just a matter of degree! But dates are important to the business, and agile provides many chances to improve estimates over time.

All contributors estimate. Those who build the software are the only ones who get to say how long they think it will take.

Break story into tasks to verify scope. In agile, design and planning go together. Designing raises many questions that dramatically impact the plan.

Come to Consensus with Planning Poker. This simple technique for deriving consensus on estimates keeps your planning meetings focused, lively, engaging, and on track. See Card 24 (next card), A Winning Hand for Planning Poker.

Decrease estimation granularity as story size increases. Estimation accuracy rapidly diminishes once stories grow beyond a few hours or a day. Don’t deceive yourself by attaching precise estimates to larger stories.

Estimate using relative sizes, not calendar days. Once a bread box, always a bread box—a story’s size doesn’t change over time. Its size relative to other stories is also constant, regardless of developer capability and availability. Remember: all contributors estimate, even in the most mature teams.