Agile Estimating
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Mike Cohn gave a presentation on agile estimating at the Norwegian Developer's Conference. He discussed using story points to estimate the effort required for user stories, rather than time-based estimates. Story points are relative values based on complexity, risk, and other factors. Planning poker is an iterative approach where estimators assign story points to stories through a process of discussion and re-estimating until consensus is reached. Ideal time estimates how long a task would take if uninterrupted, unlike elapsed time which includes delays.
Agile Estimating
- 1. Mike Cohn Norwegian Developer’s Conference 6 June 2012 Agile Estimating 1
- 2. © Copyright Mountain Goat Software ® Agenda What is agile planning? Story points Ideal time Estimating with Planning Poker 2
- 3. © Copyright Mountain Goat Software ® Iteration Backlog Code the UI 12 Write tests 8 Code middle tier 4 Update docs 6 Automate tests 5 As a user… Product Backlog As a user… As a user… As a user… As a user… 3 5 5 2 2 We’re talking about these right now 3
- 4. © Copyright Mountain Goat Software ® …to drive to Paris? …to read the last Harry Potter book? How long will it take… 4
- 5. © Copyright Mountain Goat Software ® Size Calculation Duration 300 kilograms Velocity =20 300/20 = 15 iterations Estimate size; derive duration 5
- 6. © Copyright Mountain Goat Software ® Measures of size Traditional measures of size Lines of Code Function Points Agile measures of size Story points Ideal days 6
- 7. © Copyright Mountain Goat Software ® Story points How long a user story will take (effort) Influenced by complexity, uncertainty, risk, volume of work, etc. Relative values are what is important: A login screen is a 2. A search feature is an 8. Basic math properties should hold 5+5 = 10 7
- 8. © Copyright Mountain Goat Software ® Estimating in zoo points Lion Kangaroo Rhinoceros Bear Giraffe Gorilla Hippopotamus Tiger 8
- 9. © Copyright Mountain Goat Software ® Agenda What is agile planning? Story points Ideal time Estimating with Planning Poker 9
- 10. © Copyright Mountain Goat Software ® Ideal Time How long something will take if: it’s all you work on no one interrupts you and everything you need is available 10
- 11. © Copyright Mountain Goat Software ® Elapsed time vs. ideal time Monday has 8 hours Each week has 40 hours Ideally Each day has something like: 2 hours of meetings 2 hours of email 4 hours left for the project But instead “How long will this take?” •Are you answering what is being asked? 11
- 12. © Copyright Mountain Goat Software ® Story points are additive; time-based estimates may not be1 Story points help avoid problems with unit confusion2 Two big advantages to story points 12
- 13. © Copyright Mountain Goat Software ® Confusing units Iteration Backlog Code the UI 12 Write tests 8 Code middle tier 4 Update docs 6 Automate tests 5 As a user… Product Backlog As a user… As a user… As a user… As a user… 30 50 50 20 20 13
- 14. © Copyright Mountain Goat Software ® Agenda What is agile planning? Story points Ideal time Estimating with Planning Poker 14
- 15. © Copyright Mountain Goat Software ® Planning Poker® 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 at the same time Discuss differences (especially outliers) Re-estimate until estimates converge 15
- 16. © Copyright Mountain Goat Software ® Estimator Round 1 Trond 5 Ana 5 Maria 8 Johannes 20 Round 2 8 8 8 13 Planning Poker®–an example 16
- 17. © Copyright Mountain Goat Software ® Product Backlog Items Estimate Read (and understand) a high-level, 10-page overview of agile software development in a celebrity news magazine. Read (and understand) a densely written 5-page research paper about agile software development in an academic journal. Your uncle owns a clock store and wants to sell clocks over the internet. Write a basic product backlog for him covering what he’ll need his website to do. Recruit, interview, and hire a new member for your team. Create a 60-minute presentation about agile software development for your coworkers. Wash and wax your boss’ Porsche. Read (and understand) a 150-page book on agile software development. Write a 5-page summary of this conference for your boss. Estimate these 17
- 18. © Copyright Mountain Goat Software ® Free, or I wouldn’t mention it www.PlanningPoker.com 18
- 19. © Copyright Mountain Goat Software ® mike@mountaingoatsoftware.com www.mountaingoatsoftware.com twitter: mikewcohn (888) 61-AGILE Mike Cohn 19