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| Date post: | 05-Dec-2014 |
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Business |
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Agenda • Whiskey
– Flow numbers at my bar
• Sushi – Queue and wait time at a Japanese restaurant
• More whiskey – System, System boundaries and Stable systems
• Flights and Traffic Jam – Stabilizing the system and System Thinking
• Closing Thoughts
Agenda • Whiskey
– Flow numbers at my bar
• Sushi – Queue and wait time at a Japanese restaurant
• More whiskey – System, System boundaries and Stable systems
• Flights and Traffic Jam – Stabilizing the system and System Thinking
• Closing Thoughts
Flow numbers at my bar
WIP
• The number of bottles in the bar. Bottles that have been opened, but are 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.
My bar…
I was really interested in measuring a whisky bottle
average lead time in my bar...
“The average number of work items in a stable system is equal to their average completion rate, multiplied by their average time
in the system.”
John Little, 1961
WIP = Throughput x Lead time
Please help me out...
12 bottles...
an average of 6 bottles per year…
What is the average lead time for a bottle of
whiskey?
(a) 2 months (b) 3 months (c) 6 months (d) 1 year (e) 2 years
What is the average lead time for a bottle of whiskey?
WIP = Throughput x Lead time
WIP = Throughput x Lead time
12 b = 6 b / year x Lead time
WIP = Throughput x Lead time
12 b = 6 b / year x Lead time
Lead time = 2 years
How to reduce lead time?
Doing (Limit) Done To Do
10
5
9
31 18
17
21
4
7 5
1 12
John
Suzy
Paul
Amy
WIP
Lead Time
Agenda • Whiskey
– Flow numbers at my bar
• Sushi – Queue and wait time at a Japanese restaurant
• More whiskey – System, System boundaries and Stable systems
• Flights and Traffic Jam – Stabilizing the system and System Thinking
• Closing Thoughts
Queue and wait time
very hungry
one temaki
more than 30 minutes
very frustrated
“The total wait time for a given item is the sum of its queue time
plus its working time.”
Paulo Caroli, 2013 (at AgileTrendsSP)
Total Wait =
Queue time + Work time
Different kind of work items
Different kind of work items
10 minutes
1 minute
After a few months, I went back to the restaurant and took a look at their kanban system. I noticed
that all orders follow a single queue.
Single Queue
What is the wait time?
Single Queue
Queue time
between 30 and 40 minutes
4 large orders; 1 being worked on, 3 in the queue;
each large order takes 10 minutes
Work time 1 minute
a small order takes 1 minute
Total Wait =
Queue time (between 30 and 40 minutes)
+ Work time (1 minute)
How to reduce total wait time?
Two Queues
What is the new wait time for my small order? (small
order takes priority)
In Dev Validate Backlog
10
5
9
31 17
21
4
7
5 12
Specify Execute Done
T T T T
T T T
T T
T
T T
T T T
Bugs
T
Agenda • Whiskey
– Flow numbers at my bar
• Sushi – Queue and wait time at a Japanese restaurant
• More whiskey – System, System boundaries and Stable systems
• Flights and Traffic Jam – Stabilizing the system and System Thinking
• Closing Thoughts
System
“The average number of work items in a stable system is equal to their average completion rate, multiplied by their average time
in the system.”
John Little, 1961
What is a system?
A system is an arrangement of parts within the system’s
boundaries which interact with each other, cooperating in a
process to accomplish a goal.
A system is an arrangement of parts within the system’s
boundaries which interact with each other, cooperating in a
process to accomplish a goal.
System boundaries
Stable System
My bar is a stable system: “Whenever a bottle finishes, I remove it from the bar. Then I open a new one, and add it to
the bar. “
stable system: the rate at which items enter the system equals the rate at which
they exit.
System Inbound Outbound
Agenda • Whiskey
– Flow numbers at my bar
• Sushi – Queue and wait time at a Japanese restaurant
• More whiskey – System, System boundaries and Stable systems
• Flights and Traffic Jam – Stabilizing the system and System Thinking
• Closing Thoughts
Traffic jam
System Inbound Outbound
Systems thinking (flight / boarding example)
Boarding a plane
A system is an arrangement of parts within the system’s
boundaries which interact with each other, cooperating in a
process to accomplish a goal.
So, what is the goal?
stable system: the rate at which items enter the system equals the rate at which
they exit.
System Inbound Outbound
How fast should the gate boarding happen?
System Inbound Outbound
Agenda • Whiskey
– Flow numbers at my bar
• Sushi – Queue and wait time at a Japanese restaurant
• More whiskey – System, System boundaries and Stable systems
• Flights and Traffic Jam – Stabilizing the system and System Thinking
• Closing Thoughts
Closing Thoughts
• Make work visible
• Understand the flow parameters
• Limit work in progress
• Define your system(s)
• Focus on overall system improvement
Paulo Caroli Agile Coach
Twitter: @paulocaroli
www.caroli.org @paulocaroli
Thank you! Questions?
Next are a few slides for Q and A
System of systems example
Continuous Delivery is a software development discipline that fosters
faster and more frequently releases.
And another restaurant example…
Traveling on a week day
System Inbound Outbound
0
5
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Queue
Analysis
Analysis Done
Development
Development Done
QA
Done
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To Do
Doing
Done
Doing (Limit) Done To Do
10
5
9
31 18
17
21
4
7 5
1 12
John
Suzy
Paul
Amy
WIP
Lead Time
0
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day 1 day 2 day 3 day 4 day 5 day 6 day 7 day 8 day 9 day 10
To Do
Doing
DoneWIP
Lead Time
