The document discusses limiting work-in-progress (WIP) to improve productivity. It explains that limiting WIP leads to better quality, faster delivery, and less stress by improving flow. Too much WIP results in long wait times and slow response to changes, while just enough WIP keeps work moving with some idle time used for improvements. The document advocates starting with small WIP limits and using slack time as a signal to address bottlenecks. An exercise demonstrates teams completing a paper airplane assembly task faster with limited WIP by reducing waste and improving flow.

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Limiting WIP:
Doing Less to Do More
Hunter Tammaro & Julie Wyman

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Work in Progress
(WIP)
Any partly finished product
or materials in an incomplete step
of a process
Completed work in one process
may be WIP to a higher-order
process
WIP does not provide any value to
a customer

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First, some theory…

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Improved quality
Better problem solving
Fewer errors
Lower stress
Increased productivity

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Faster Delivery & Feedback
Value
Returned
4 Parallel Efforts
WIP = 4
Time
1 Parallel Effort
WIP = 1
Time
Value
Returned

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Little’s Law
• 𝐶𝑦𝑐𝑙𝑒 𝑡𝑖𝑚𝑒 =
+,-
./0123/425
• Hard to sustainably increase
throughput
• Not as hard to reduce WIP

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Does your team determine its
(Sprint) capacity based of on
8 hours a day?
Less? More?

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Utilization, WIP and flow

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Too much
WIP
Fully utilized, but spend
most of the time waiting
Slow flow through the
system
Slow to respond to change

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On a software team
Total Active
Time:
Total Waiting
Time:
Analysis
(2 days)
Development
(5 days)
Testing
(1 day)
Deploy
(1 day)
Waiting for
development (3 days)
Waiting for
testing (6 days)
Waiting to
deploy (4 days)

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On a software team
Total Active
Time:
9 days
Total Waiting
Time:
13 days
Analysis
(2 days)
Waiting for
development (3 days)
Development
(5 days)
Waiting for
testing (6 days)
Testing
(1 day)
Waiting to
deploy (4 days)
Deploy
(1 day)

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Just enough
WIP
Team members sometimes idle,
but work almost always moving
Rapid flow through the system
Short response time reduces
effect of impediments

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Idle team members?!
• Remove blockers
• Help other team members
• Process improvement
• Address technical debt
• Improve your craft
• Take a walk to get some coffee

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Slack time as a signal
WIP limits help individuals find ways
to improve the flow of the entire team
Are there issues upstream in the process that can
be resolved?
Are there issues downstream in the process?
Adjust WIP or team composition until
flow is optimized

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Setting WIP limits
Requirements Ready Analysis Development Validate Done
3 5 34
Doing Done Doing Done
Just start…
Observe
Adjust from
there
Cycle Time

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Prove It!
“Plane Game”
https://growingagile.co.za/2015/02/aeroplane-game/

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Practice Round
Compete to make paper airplanes in teams
of six
One team member at each station
One team member times the
construction of the colored plane
One team member times the entire
round

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Round 1
Work as fast as you can in a first-in-first-out
basis
After 10 planes are completed and tested, use
the worksheet to record:
The time to make all 10 planes
The time to make the colored plane
The number of incomplete planes in
progress

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Round 2
This time, work with a WIP limit of 1 per
station
E.g. Station 1 can’t start on the next plane
until Station 2 takes their sheet
After 10 planes are completed and tested, use
the worksheet to record:
• The time to make all 10 planes
• The time to make the colored plane
• The number of incomplete planes in
progress

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In which round did you
complete all 10 planes faster?
Which round took your team
more time to make the
colored plane?
In which round was there
more waste?
Discussion
In which round did you feel
more stressed?
Which round felt more like
how you work in real life?

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Key Takeaways
Limiting WIP…
• Creates a better-quality product
faster
• Leads to quicker realization of
value and better feedback
• Improves the functioning of the
team by making bottlenecks visible
Remember to…
focus on flow, not utilization

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Additional Resources

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“Multitasking is Evil”
https://agileconnection.com/article/multitasking-evil

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Multitasking is Evil
Round 1
You are assigned three projects,
which you will work one at a time.
Project 1: Write the numbers 1-15 in the 1st
column.
Project 2: Write the letters Z->N in the 2nd
column.
Project 3: Write the Roman numerals IV-
XVII in the 3rd column.
1-15 Z-N IV-XVII
1 Z IV
2 Y
3 X
Work column-by-column
until you complete all 3
projects.
Write down the time you
finish.

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Multitasking is Evil
Round 2
You are assigned three projects,
which you will work all at once.
Project 1: Write the numbers 1-15 in the 1st
column.
Project 2: Write the letters Z->N in the 2nd
column.
Project 3: Write the Roman numerals IV-
XVII in the 3rd column.
1-15 Z-N IV-XVII
1 Z IV
2 Y V
3
Work row-by-row until
you complete all 3 projects.
Write down the time you
finish.

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Discussion
• In which round did you complete your
first project faster?
• Which round took you more time to
complete all three projects?
• In which round did you make more
mistakes?
• In which round did you feel more
stressed?
• Which round felt more like how you work
in real life?

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Links
• Huffington Post article on multitasking with statistics
• Blog posts:
• How to set initial WIP limits
• How Scrum and Kanban approach WIP differently
• Constraints in Scrum and Kanban
• Books:
• Lean from the Trenches – Henrik Kniberg

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