Alternatives to Agile Estimation - A Team Perspective

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Alternatives to Agile Estimation - A Team Perspective

  1. 1. ALTERNATIVES to AGILE ESTIMATION NEIL KILLICK neilkillick.com neil_killick #NoEstimates
  2. 2. AND WHEN WHAT WILL I GET
  3. 3. ESTIMATING OR GUESSING?
  4. 4. MAKING PREDICTIONS <> PREDICTABILITY
  5. 5. USE *REAL* CONSTRAINTS
  6. 6. KEEP TEAMS TOGETHER
  7. 7. USE XP PRACTICES ● Continuous integration ● TDD/BDD ● Pair programming ● Clean code
  8. 8. DELIVER EARLY & OFTEN
  9. 9. FOCUS ON FLOW
  10. 10. ITERATE *AND* INCREMENT
  11. 11. BACKLOG = OPTIONS ● You will NOT build the whole backlog ● Knowing this is empowering
  12. 12. DOES SIZE MATTER? 8 Smaller, cheaper (?) awesome feature Awesome feature 13
  13. 13. FOCUS ON VALUE, NOT COST ● Iterative Funding ● Emergent Value
  14. 14. USE A SLICING HEURISTIC ● Explicit policy for breaking up work, e.g. "A story must have only one acceptance test" ● Slice stories JIT (e.g. in Sprint Planning) ● Can add to "Definition of Ready"
  15. 15. WHY IS THIS BETTER THAN ESTIMATING? ● Explicitly promotes the good practice of splitting work to be done ● Avoids cognitive biases ● Easy to measure effectiveness (e.g. mean & median cycle time within x%)
  16. 16. LITTLE'S LAW IS KEY CYCLE TIME = WIP / THROUGHPUT
  17. 17. ● Size of premises ● No. & size of ovens CONSTRAINTS REDUCE VARIABILITY AND LIMIT WIP ● No. of chefs & drivers ● Delivery radius
  18. 18. ● Avg. wait time (hours) = Number of orders in progress (WIP) / Avg. orders completed in an hour (throughput) ● Assume throughput is 50 ● Using Little's Law, 0.5 = x / 50 ● x = 25 ● We should only take on 25 orders at a time MAX. 30 MINUTE WAIT FOR CUSTOMERS
  19. 19. WHAT IF WE TAKE ON MORE ORDERS?
  20. 20. TAKING ON MORE ORDERS MAY INCREASE WAIT TIME ● Now our WIP is 30 orders ● x = 30 / 50 ● x = 0.6 hours = 36 minutes ● If we can actually deliver 60 pizzas per hour, wait time will not increase
  21. 21. LIMIT WIP, LOW CYCLE TIME WIP limits
  22. 22. CYCLE TIME DISTRIBUTION ● Measure actual cycle time to identify outliers ● Measure mean and median averages
  23. 23. EASY TO MEASURE & SHOW ● Update cycle time at daily standup ● Use coloured dots to represent number of days An awesome feature that's taken 4 days
  24. 24. IN SUMMARY ● Real constraints breed creativity ● Keep teams together ● Use XP practices for technical excellence ● Put the "iterate" back into iterations!
  25. 25. IN SUMMARY ● Treat the backlog as options ● Focus on value, not cost ● Slice work using a heuristic ● Limit WIP and measure cycle times
  26. 26. Thank you NEIL KILLICK neilkillick.com neil_killick #NoEstimates

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