Agile estimating 12112013 - Agile KC Dec 2013

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Paul Carter's session on estimating for the Agile KC group. December 11, 2013

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Agile estimating 12112013 - Agile KC Dec 2013

  1. 1. The Power of Story Point Estimating
  2. 2. Trends in Agile Estimating  Story point estimating using Fibonacci sequence is most common • • • • • • • • Story points with Fibonacci 40% Story points (FP, LOC, hours, ideal days) 18% T-Shirt sizes 10% Function points 8% Hours 9% Other 8% Ideal Days 5% Lines of code 1% Source: Forrester Research Q32013 Global Agile Survey
  3. 3. Research Findings  “The way we do story point estimation gives better estimates than hourly estimates as they are more accurate and have less variation.” (Forrester Group Research)  “Story point estimation cuts estimation time by 80% allowing teams to do more estimation and tracking than a typical waterfall team. A telecom company noticed that estimated story points with planning poker was 48 times faster than waterfall estimation practices in the company and gave as good or better estimates.” (Forrester Group Research)  “Story points are therefore faster, better, and cheaper than hours and the highest performing teams completely abandon any hourly estimation as they view it as waste that just slows them down.” (Forrester Group Research)  “New research findings show that agile estimation is astoundingly more accurate than traditional project estimation.” (Microsoft)
  4. 4. Why do we Estimate?     Cost and schedule transparency Manage perceptions Set clear expectations Enable Product Owner to prioritize and maximize business value  Enable team to establish realistic goals and commitments
  5. 5. Agile Estimating Best Practices size is estimated, velocity is measured, duration is derived, cost is calculated 1. Estimate Size • • INVEST User Stories Fibonacci Number Sequence – – – 2. Measure Velocity • 3. Use standard deviation Calculate Cost • 5. 4-6 Sprints to determine velocity Derive Schedule • 4. Anchor Story Mike Cohn’s Planning Poker Wall Technique Apply math formulas Inspect and Adapt / Recalibrate
  6. 6. Agile Concept Relative Sizing is used to manage the inherent uncertainty in estimating large requirements. Do Not Do Estimate by units of time Size by complexity, comparing one story to another
  7. 7. Fibonacci Numbers
  8. 8. Leo “Liber Abaci”
  9. 9. Using Fibonacci 1. INVEST User Stories 2. Comparative size the Stories using the modified Fibonacci Sequence 3. Choose an Anchor Story
  10. 10. Size the Jedis
  11. 11. Why Story Points? Relative Sizing is used to manage the inherent uncertainty in estimating large requirements. With significant uncertainty, the more precise we are, the less accurate we are.
  12. 12. Story Point Benefits  Provides meaningful information to drive prioritization based on business value  Fosters communication & collaboration  Enables focus on the big picture  Avoids unnecessary precision  Improves team psychology  Estimation is easier & faster when considered in relative terms
  13. 13. Agile Concept The average number of story points a team gets done in a Sprint. “Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.”
  14. 14. Understanding Velocity  Predictability  What can be done by a specific date  When something can be completed  How much business value (work) a team can deliver over time  Accuracy  Developing a consistent velocity allows for more accurate release and sprint planning
  15. 15. Forecasting the Release Date & Cost  Inputs     Team member allocation (from capacity planning) Team Velocity (4 – 6 sprints) Apply Standard Deviation Forecast Formulas  Outputs  Project Cost Estimate  Project Schedule Forecast
  16. 16. Forecasting Formulas  Derive Schedule  Determine Velocity  Apply Standard Deviation to obtain the range  (Total Story Points / Velocity) + 1 = Number of Sprints +/Standard Deviation  Estimate Cost  Number of Sprints * Allocation * Number of Resources * Bill Rate = Estimated Labor Cost +/- Standard Deviation
  17. 17. Forecast Schedule Example  Derive Schedule  Product Backlog = 200 pts  Sprint Progress • • • •      Sprint 1 = 30 pts Sprint 2 = 20 pts Sprint 3 = 45 pts Sprint 4 = 25 pts Remaining points = 80 Velocity = 30 Standard Deviation = 11 Remaining Story Points / Velocity = Number of Sprints = 2.6 Forecast is 3 more Sprints +/-1 Sprint when Standard Deviation is applied
  18. 18. Forecast Cost Example  Estimate Cost  Number of Sprints * Resources * Allocation converted to hours worked in a Sprint * Bill Rate  Range of Sprints was 6 to 8  3 Team members at 80% allocation (96 hours/week)  Bill Rate = 80.00/hr  Cost Estimate Range is $138,240 - $184,320  Avg Cost Per Story Point = $768 • (Resource*Allocation*Bill Rate)/Avg Story Pts  Avg Cost Per Sprint = $23,040
  19. 19. Forecast Calculator
  20. 20. Publish Your Release Forecast  After all user stories are Sized, and team Velocity is measured, then the Duration can be derived, and Cost calculated  The forecast is then published as a project Release Date and Labor Expense size is estimated, velocity is measured, duration is derived, cost is calculated
  21. 21. Agile Concept Regularly revisit estimates and forecast “At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.”
  22. 22. Agile Estimating is Efficient  Story Point Technique  6 - 9 months  5360 - 7680 hours  Effort to forecast cost & schedule: 2 hours  Traditional Technique  6 - 9 months  5120 - 7500 hours  Effort to forecast cost & schedule: 30 hours
  23. 23. Summary  Power of Story Points using Fibonacci  Helps Product Owner to prioritize to maximize business value  Enables clear communication to set expectations  Helps team set realistic goals & commitments  Enables cost & schedule forecast accuracy  Always use ranges for estimates & numbers for facts size is estimated, velocity is measured, duration is derived, cost is calculated

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