does sfo 2016 san francisco - julia wester - predictability: no magic required
TRANSCRIPT
Predictability No magic required
Julia WesterImprovement Coach & Team Manager
EverydayKanban.com@[email protected]
Adjective
Expected, especially on the basis of previous or known behavior
[good or bad!]
Predictable[pri-dik-tuh-buh l]
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USUALLYGREAT!USUALLY
HORRIBLE!USUALLY________!
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How many telephone lines are needed to avoid blocked calls given Random arrivals Random durations
Pulling answers from randomness
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The mathematical study of waiting lines, or queues.
Can quantify relationships between queue size, capacity utilization and cycle times
Queueing Theory was the solution
capacity utilization (rho)
Queue size (N)
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TODAY’S TALK Why queues matter Choices we can make about
queues Monitoring your predictability
indicators
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Why Queues Matter
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Queues are the waiting work in a system
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Mo’ queue, Mo’ problems Longer average
cycle times Wider range of
cycle times More mgmt
overhead Reduced
motivation & quality
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Our workflows are chains of queues
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As interpreted by Don Reinertsen
Aesop’s Fable:
The Tortoise and the Hare
Finish
Predictability ≠ fastestUNLESS
you can consistently be that fast.
To become more predictable…USUALLY
DONE IN 2 to 200 DAYS!
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USUALLYDONE IN 25 to 35 DAYS! reduce the range of
probable outcomes.
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Choices we can make about queues
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Choice: Use a push system or pull system?1 queue per server
1 queue multiple servers
PullSystem
PushSystem
Which one do you use?
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normal
stopped
Slower, but consistentWide variation
PullSystem
PushSystem
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Choice: What factors used to prioritize?
Your policy here!
FIFO/S PRIORITY
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FIFO
Non-FIFO
Wider variation
Less variation.Feasible?
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Choice: Deliver large or small batches?Once a month
Once a week
Once a weekOnce a month
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Wider variation Less
variation
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Monitoring your predictability indicators
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Cycle time ranges: Lagging indicatorNovOctoberSeptemberAugustJuly
Good clustering
Can we reduce the outliers?
95%: 45 days or less
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Queue size: a leading indicator
Which lane is going faster?
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CFD: Demonstrates the relationshipWork units
Time
Queue sizeCycle Time
To Do
Design
Create
Verify
Deliver
18
10
1.5
2.5
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Queue Size: predicting predictability issues
Bigger queues lead to longer cycle times, less predictability
Smaller queues lead to shorter cycle times, more predictability
Work-In-Process (hidden queues?)
Queued work
9
20
10
2
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• Remember, you have control over predictability! • Get baseline measures of queue size/cycle
times.• Make informed choices about handling queues.• Monitor queues to anticipate and correct issues
before they negatively impact cycle times.
@everydaykanban
References and Inspiration
www.leankit.com
To receive a copy of:
• The slide deck for today’s presentation
• LeanKit’s 1st Annual Lean Business report
Send an email to: [email protected]: DOES16