John Little,whiskey and flow           Paulo Caroli               Agile Coach           pcaroli@thoughtworks.com          ...
Agenda•   Flow numbers at the bar•   Flow numbers at the Kanban board•   Little’s Law•   Q&A
Agenda•   Flow numbers at the bar•   Flow numbers at the Kanban board•   Little’s Law•   Q&A
Flow numbers at the bar
WIP• The number of bottles in the bar. Bottles  that have been opened, but not yet  empty.
Lead time• The time between the bottle is added to  the bar and the bottle comes out of the  bar (empty).
Cycle time• The time between two successive empty  bottles leaving the bar
Throughput• The rate at which bottles are passing through  the bar.
Batch size• The size of the bottles.
Agenda•   Flow numbers at the bar•   Flow numbers at the Kanban board•   Little’s Law•   Q&A
Agenda•   Flow numbers at the bar•   Flow numbers at the Kanban board•   Little’s Law•   Q&A
Flow numbers at the Kanban board
To Do                         Doing         Done                                     1210                                 ...
To Do                         Doing         Done                              WIP                                     1210...
To Do                             Doing              Done                                                     Day 6       ...
To Do                         Doing                      Done                                            Cycle time       ...
To Do                         Doing         Done                                     1210                                 ...
To Do                           Doing         Done                                             12        10               ...
Agenda•   Flow numbers at the bar•   Flow numbers at the Kanban board•   Little’s Law•   Q&A
Agenda•   Flow numbers at the bar•   Flow numbers at the Kanban board•   Little’s Law•   Q&A
Little’s Law
To Do                         Doing         Done                              WIP                                     1210...
To Do                        Doing                  Done                             WIP                                  ...
To Do                         Doing              Done                              WIP                                    ...
To Do                         Doing              Done                               WIP                                   ...
“The average number of work items in a stable system is equalto their average completion rate, multiplied by their average...
WIP = Throughput x Lead time
The numbers at my bar• My bar has 12 bottles of whiskey• I finish an average of 6 bottles per year• What is the average le...
?
WIP = Throughput x Lead time 12 b= 6 b / year x Lead time     Lead time = 2 years
Cycle time is the inverse of        Throughput
WIP = Throughput x Lead time            <=>Lead Time = WIP x Cycle Time
Lead Time = WIP x Cycle Time 2 years = 12 b x Cycle time
Cycle time = 1 year / 6 b
Converting to months…
Cycle time = 2 months / 1 b
In average, I finish a bottle every            2 months
Agenda•   Flow numbers at the bar•   Flow numbers at the Kanban board•   Little’s Law•   Q&A
Agenda•   Flow numbers at the bar•   Flow numbers at the Kanban board•   Little’s Law•   Q&A
Questions to the audience•   What happens if my bar size reduces by half?•   What if I only buy small bottles (half size)?...
John Little,whiskey and flow           Paulo Caroli               Agile Coach           pcaroli@thoughtworks.com          ...
Thank you!         Questions?feedback please: @paulocaroli www.KanbanAndBeyond.com                  Paulo Caroli          ...
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John little, whiskey and flow

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a great way for understanding flow numbers and Little's law

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John little, whiskey and flow

  1. 1. John Little,whiskey and flow Paulo Caroli Agile Coach pcaroli@thoughtworks.com Twitter: @paulocaroli
  2. 2. Agenda• Flow numbers at the bar• Flow numbers at the Kanban board• Little’s Law• Q&A
  3. 3. Agenda• Flow numbers at the bar• Flow numbers at the Kanban board• Little’s Law• Q&A
  4. 4. Flow numbers at the bar
  5. 5. WIP• The number of bottles in the bar. Bottles that have been opened, but not yet empty.
  6. 6. Lead time• The time between the bottle is added to the bar and the bottle comes out of the bar (empty).
  7. 7. Cycle time• The time between two successive empty bottles leaving the bar
  8. 8. Throughput• The rate at which bottles are passing through the bar.
  9. 9. Batch size• The size of the bottles.
  10. 10. Agenda• Flow numbers at the bar• Flow numbers at the Kanban board• Little’s Law• Q&A
  11. 11. Agenda• Flow numbers at the bar• Flow numbers at the Kanban board• Little’s Law• Q&A
  12. 12. Flow numbers at the Kanban board
  13. 13. To Do Doing Done 1210 1 John 7 5 49 Suzy 21 18 31 Paul 17 5 Amy
  14. 14. To Do Doing Done WIP 1210 1 John 7 5 49 Suzy 21 18 31 Paul 17 5 Amy
  15. 15. To Do Doing Done Day 6 Day 1 12 1010 10 John 1 7 Lead Time 5 49 Suzy 21 18 31 Paul 17 5 Amy
  16. 16. To Do Doing Done Cycle time 1210 1 John Day 1 7 Day 2 5 49 Suzy 21 Day 3 18 31 Paul 17 5 Amy
  17. 17. To Do Doing Done 1210 1 John 7 5 49 Suzy 21 18 31 Paul 17 Throughput 5 Amy
  18. 18. To Do Doing Done 12 10 1 JohnBatch size 7 5 4 9 Suzy 21 18 31 Paul 17 5 Amy
  19. 19. Agenda• Flow numbers at the bar• Flow numbers at the Kanban board• Little’s Law• Q&A
  20. 20. Agenda• Flow numbers at the bar• Flow numbers at the Kanban board• Little’s Law• Q&A
  21. 21. Little’s Law
  22. 22. To Do Doing Done WIP 1210 1 John 7 5 49 Suzy 21 18 31 Paul 17 5 Amy
  23. 23. To Do Doing Done WIP 1210 Demand Throughput 1 John 7 5 49 Suzy 21 18 31 Paul 17 5 Amy
  24. 24. To Do Doing Done WIP 1210 1 John 7 5 49 Suzy 21 18 31 Paul Lead Time 17 5 Amy
  25. 25. To Do Doing Done WIP 12 10 1 John 7 5 4 9 Suzy 21 18 31 Paul Lead Time 17 5 Amy# WIP is proportional to average lead time
  26. 26. “The average number of work items in a stable system is equalto their average completion rate, multiplied by their average time in the system.” John Little, 1961
  27. 27. WIP = Throughput x Lead time
  28. 28. The numbers at my bar• My bar has 12 bottles of whiskey• I finish an average of 6 bottles per year• What is the average lead time for a bottle of whiskey?
  29. 29. ?
  30. 30. WIP = Throughput x Lead time 12 b= 6 b / year x Lead time Lead time = 2 years
  31. 31. Cycle time is the inverse of Throughput
  32. 32. WIP = Throughput x Lead time <=>Lead Time = WIP x Cycle Time
  33. 33. Lead Time = WIP x Cycle Time 2 years = 12 b x Cycle time
  34. 34. Cycle time = 1 year / 6 b
  35. 35. Converting to months…
  36. 36. Cycle time = 2 months / 1 b
  37. 37. In average, I finish a bottle every 2 months
  38. 38. Agenda• Flow numbers at the bar• Flow numbers at the Kanban board• Little’s Law• Q&A
  39. 39. Agenda• Flow numbers at the bar• Flow numbers at the Kanban board• Little’s Law• Q&A
  40. 40. Questions to the audience• What happens if my bar size reduces by half?• What if I only buy small bottles (half size)?• What if I double my drinking average?• Q&A
  41. 41. John Little,whiskey and flow Paulo Caroli Agile Coach pcaroli@thoughtworks.com Twitter: @paulocaroli
  42. 42. Thank you! Questions?feedback please: @paulocaroli www.KanbanAndBeyond.com Paulo Caroli Agile Coach pcaroli@thoughtworks.com Twitter: @paulocaroli

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