Agile Estimation Techniques
Agile estimation techniques are lightweight methods used by agile teams to estimate the size, effort, or complexity of work items, including story points, planning poker, T-shirt sizing, and relative estimation.
Explanation
Agile estimation techniques differ from traditional estimation in that they focus on relative sizing rather than absolute time estimates. Story points are the most common unit, representing the overall effort, complexity, and uncertainty of a user story relative to other stories. Planning poker (a form of Wideband Delphi) is a popular technique where team members independently estimate, reveal simultaneously, and discuss differences before converging.
Other agile estimation techniques include T-shirt sizing (using S, M, L, XL categories for rough sizing), affinity estimation (grouping stories by similar size), and ideal days. These techniques are designed to be quick, collaborative, and to leverage the collective wisdom of the team rather than relying on a single estimator.
Agile estimation is intentionally imprecise at the individual story level but becomes quite accurate in aggregate over multiple iterations. Teams use their velocity (the average number of story points completed per iteration) to forecast delivery timelines and capacity. The emphasis is on consistency of estimation rather than absolute accuracy.
Key Points
- •Focus on relative sizing rather than absolute time estimates
- •Story points measure effort, complexity, and uncertainty
- •Planning poker uses independent estimation with group convergence
- •Aggregate accuracy improves over multiple iterations via velocity tracking
Exam Tip
Know that agile estimation focuses on relative sizing, not absolute hours. Planning poker combines independent estimation with group discussion, similar to Wideband Delphi.
Frequently Asked Questions
Related Topics
Wideband Delphi
Wideband Delphi is a consensus-based estimation technique that extends the Delphi method by adding team discussion between anonymous estimation rounds to improve estimate accuracy.
T-Shirt Sizing
T-shirt sizing is an agile estimation technique that uses relative size categories (XS, S, M, L, XL) to quickly classify the effort or complexity of work items without precise numerical estimates.
Rolling Wave Planning
Rolling wave planning is an iterative planning technique where near-term work is planned in detail while future work is planned at a higher level, with details added as the project progresses.
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