Agile estimation & planning
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This document discusses agile estimation and planning. It defines an estimate as an unbiased process to predict duration or cost, and notes that estimates become more accurate over time as uncertainty decreases. It recommends using story points for estimating, which are relative units based on size, complexity and unknowns. The document also describes planning poker, an iterative group estimation technique where estimators assign cards to stories until estimates converge.
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Agile estimation & planning
- 1. Agile Estimation & Planning GrapeCity Inc Apr 12, 2012 © 2011 GrapeCity inc.
- 2. What is an estimate ? Unbiased, analytical process to predict the duration or cost of a project © 2011 GrapeCity inc. 2
- 3. By definition estimate is not accurate © 2011 GrapeCity inc. 3
- 4. Cone of Uncertainty © 2011 GrapeCity inc. 4
- 5. Cone of Uncertainty © 2011 GrapeCity inc. 5
- 6. Story Points © 2011 GrapeCity inc. 6
- 7. Story Points • Probably the most commonly used estimating unit among agile teams today – Name is derived from agile teams commonly expressing requirements as “user stories” • Based on combination of the size , unknowns and complexity of the work • Unit less but numerically relevant estimates – A 10 – point user story is expected to take twice as long as a 5 – point user story © 2011 GrapeCity inc. 7
- 8. We are good in comparing things © 2011 GrapeCity inc. 8
- 9. Time is not persistent © 2011 GrapeCity inc. 9
- 10. Three key advantages • Estimating in story points: – Forces the use of relative estimating . Studies have shown we are better at this • Focuses us on estimating the size , not the duration – We derive duration empirically by seeing how much we complete per iteration • Puts estimates in units that we can add together – Time based estimates are not additive © 2011 GrapeCity inc. 10
- 11. Zoo points What value in “zoo points” would you put Lion on these zoo Kangaroo animals? Rhinoceros Bear Giraffe Gorilla Hippopotamus Tiger © 2011 GrapeCity inc. 11
- 12. Estimating in Trees, Probing the Unknown © 2011 GrapeCity inc. 12
- 13. Estimating in Trees, Probing the Unknown © 2011 GrapeCity inc. 13
- 14. Estimating in Trees, Probing the Unknown © 2011 GrapeCity inc. 14
- 15. Estimating in Trees, Probing the Unknown © 2011 GrapeCity inc. 15
- 16. Estimating in Trees, Probing the Unknown © 2011 GrapeCity inc. 16
- 17. Planning Poker for estimating An iterative approach to estimating Steps • Each estimator is given a deck of cards, each card has a valid estimate written on it • Customer/Product owner reads a story and it’s discussed briefly • Each estimator selects a card that’s his or her estimate • Cards are turned over so all can see them • Discuss differences (especially outliers) • Re-estimate until estimates converge © 2011 GrapeCity inc. 17
- 18. Estimating without Planning Poker Product Owner Team starts thinking about how long the story will take (in ideal man-days) © 2011 GrapeCity inc. 18
- 19. Estimating without Planning Poker Mr A believes that he knows exactly what needs to be done, so he thinks this will take 3 days. Mr B and C are more pessimistic. Mr D and E are slacking off. So Mr A says "3 days". © 2011 GrapeCity inc. 19
- 20. Estimating without Planning Poker This makes B and C confused. They start doubting their own estimates. As you can see, the rest of the team has been heavily influenced by A, just because A spoke up first. © 2011 GrapeCity inc. 20
- 21. Estimating with Planning Poker Imagine that each team member is holding a deck of cards, containing the following cards: Product Owner Once again, the team starts thinking about how long the story will take. © 2011 GrapeCity inc. 21
- 22. Estimating with Planning Poker This time nobody blurts anything out. Instead they all have to present a card, face down, containing their estimate. When they are done, all cards are turned over simultaneously, revealing everyone's estimates © 2011 GrapeCity inc. 22
- 23. Estimating with Planning Poker Whoops! Big divergence here. The team, in particular Mr A and Mr C, need to discuss this story and why their estimates are so wildly different. After some discussion, Mr A realizes that he has forgotten some important tasks that need to be included in the story. Mr C realizes that, with the design that Mr A presented, the story might be smaller than 20. © 2011 GrapeCity inc. 23
- 24. Why Planning Poker works • Those who will do the work ,estimate the work. • Estimators are required to justify estimates • Combining of individual estimates through group discussion leads to better estimates. • Emphasizes relative rather than absolute estimating • Estimates are constrained to a set of values so we don’t waste time in meaningless arguments • Everyone’s opinion is heard. © 2011 GrapeCity inc. 24
- 25. Release Planning © 2011 GrapeCity inc. 25
- 26. © 2011 GrapeCity inc. 26
- 27. Release Planning Meeting Release Planning Meeting Release Plan Sprint 1 Sprint 2 Sprint 3 Sprints 4−7 © 2011 GrapeCity inc. 27
- 28. An example with velocity = 14 Story A Story F Sprint 1 Sprint 3−4 5 3 Story A Story B Story H Story J 5 8 13 Story B Story G Story I 8 Story E 8 3 5 Story H 1 Story C 13 3 Sprint 2 Story I Story F Story D 5 Story C 3 5 3 Story J Story G Story E Story D 8 3 1 5 © 2011 GrapeCity inc. 28
- 29. Projections based on velocity 40 Mean (Best 3) = 37 Mean (Last 8) = 33 30 Mean (Worst 3) = 28 20 10 0 1 2 3 4 5 6 7 8 9 © 2011 GrapeCity inc. 29
- 30. Extrapolate from velocity Assume 5 sprints left At our slowest velocity,we’ll end here (5 × 28) At our average velocity,we’ll end here (5 × 33) At our best velocity, we’ll end here (5 × 37) © 2011 GrapeCity inc. 30
- 31. Burndown charts © 2011 GrapeCity inc. 31
- 32. An iteration burndown chart © 2011 GrapeCity inc. 32
- 33. A release burndown chart © 2011 GrapeCity inc. 33
- 34. Thank You © 2011 GrapeCity inc. 34
Editor's Notes
- The vertical axis contains the degree of error that has been found in estimates created by skilled estimators at various points in the project. Estimates created very early in the project are subject to a high degree of error. Estimates created at Initial Concept time can be inaccurate by a factor of 4x on the high side or 4x on the low side (also expressed as 0.25x, which is just 1 divided by 4). The total range from high estimate to low estimate is 4x divided by 0.25x, or 16x.
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- http://www.crisp.se/planningpoker
- http://www.crisp.se/planningpoker
- They thought they has 780 hrs of work . It went up as we figured out something's are more tough and discovered some new stuff . Team discovered they cant deliver on time . The product owner dropped some portions of it
- On this burndown chart, the team started a project that was planned to be eleven two-week sprints. They began with 200 story points of work. The first sprint went well and from the chart you can infer that they had around 180 story points of work remaining after the first sprint. During the second sprint, however, the estimated work remaining actually burned up. This could have been because work was added to the project or because the team changed some estimates of the remaining work. From there the project continued well. Progress slowed during sprint 7 but then quickly resumed.