This document discusses challenges to Kanban principles and provides examples to illustrate how those principles can be applied. It begins with an example of modeling lead time and throughput at a drive-thru to show how these metrics can be used. It then discusses how NASA successfully applied the principles of limiting work in progress and validated learning incrementally to achieve major goals like landing on the moon. The document argues these principles can be used in any organization to improve predictability and outcomes.

2. Let’s Challenge Preconceptions
• “Estimates inform us when things will finish”
• Kanban uses difficult maths
• You can’t limit WIP in big organisations
• Validated learning doesn’t deliver anything
© 2013 ripplerock Dan Brown @KanbanDan

3. • How good an estimate would you have in
30 seconds? 30 minutes?
5 minutes? 2 weeks?

5. Everything that doesn’t have a cross on it is a whole galaxy
“Your friends can’t help you now?”

6. Let’s Substitute Predictability for Estimation
• This presentation contains Maths.
• I will be asking you some questions.
• But …
• I have an example to make it as painless as possible...
© 2013 ripplerock Dan Brown @KanbanDan

7. Let’s go to the Drive-Thru
• What is a Drive-Thru
• Typically found in fast food
• You stay in your car
• You drive around the building
• You:
– Order your food
– Pay for your food
– Collect your food
• All through your car window
• After you collect you drive
away with your food
© 2013 ripplerock Dan Brown @KanbanDan

8. Drive-thu example
• Let me define my terms to be clear
• Lead Time - the time from a particular
customer driving up, to driving away with
a burger
• Throughput Rate - how frequently customers
drive away with food
• Original Drive-Thru only had 1 window
• So if it takes 90s to get served with 1 window:
– Avg Lt is 90 seconds
– Avg Tr is 1 customer per 90 seconds

9. Fast Forward in time…
• Some people worked out it could be improved
• 2 Window system
– order & pay at first window (45s),
– collect at second window(45s)
• How does that affect our measurements?
– Avg Tr is now 1 every 45s, Avg Lt is now 90s
© 2013 ripplerock Dan Brown @KanbanDan

10. Pop Quiz
• What happens with 3 ‘windows’?
• 30 seconds to order
• 30 seconds to pay
• 30 seconds to collect
• What is Lead Time?
• 90s
• What is Throughput rate?
• 1 every 30s
© 2013 ripplerock Dan Brown @KanbanDan

11. But who cares?
• Your customers care!
• Throughput Rate:
– How frequently new Features come “off the
line”
• Lead Time:
– “when will this Feature be done if we started
now”
• Allows us to predict when whole Product will
be done
© 2013 ripplerock Dan Brown @KanbanDan

12. Dan, when will the product be done?
• If you deliver 1 work item every 2 days
• Your Tr = 0.5 items per day (units must match)
• If your Lt is 11 days …
• If you have 100 work items to finish
• Your total Product Time = 11 + ( 100 / 0.5 )
• Pt = 211 days
• Product Time for a new project is:
– Lt + ( Number of Features / Tr )
• But take note of variance to the averages of Lt & Tr to give
tollerances!
© 2013 ripplerock Dan Brown @KanbanDan

13. But Dan, how can I use maths to help me?
• You can use Little’s Law (for stable systems) to
link Tr, Lr and WIP in a simple equation… but
• We don’t have time for that right now.
• You could always come talk to me afterwards…
• Or attend an LKU Accredited Kanban Course -
‘Real Kanban’ for example 
www.ripple-rock.com/training/real-kanban.aspx
© 2013 ripplerock Dan Brown @KanbanDan

14. Back to the drive-thru
• 2 windows are open, but
• Window 2 actually takes 50s
• Window 1 takes only 40s
• What is the Tr?
• WIP is 2, Tr = 1 per 50s,
• so Lt = 2 * 50s = 100s ( thanks to Little’s Law)
• Why is this not 90s?
© 2013 ripplerock Dan Brown @KanbanDan

15. But in the real world…
• …we get a queue between windows of 3 cars
(limited by space)
• WIP isn’t 2 then, it’s really the 2 at windows
plus the 3 queuing, so what is the WIP now?
• 5!
© 2013 ripplerock Dan Brown @KanbanDan

16. So what difference does that make?
• With WIP of 5
• Tr is still = 1 per 50s
• Lt = Tr * WIP
• What’s the new Lt?
• 250s!
• Increasing the WIP without reducing the
Tr increases the Lt!
• Maths done
© 2013 ripplerock Dan Brown @KanbanDan

17. Oh, and by the way

18. How do you make a footprint on the moon?
• You finish “One small step” at a time!
• NASA says:
“Do one thing at a time,
with supreme excellence.”
• A colleague once told me:
“As soon as our clients work out that all
they have to do is ‘put everything into
an ordered list, then finish them one at
a time’ we’ll be out of a job”
• We keep saying it, but we’re still in jobs…
© 2013 ripplerock Dan Brown @KanbanDan

19. NASA – Limited WIP in Action
• Do One Thing At A Time
• We’ve seen the maths and we can measure
why it works
• In the 1950s and 1960s
NASA were living it
• And they still are…
© 2013 ripplerock Dan Brown @KanbanDan

20. What is their “one thing” now
• Who supplies the International Space Station?
© 2013 ripplerock Dan Brown @KanbanDan

21. So what are NASA doing?
© 2013 ripplerock Dan Brown @KanbanDan

22. All of NASA?
• They have a separate division called the JPL
• They do the space
telescopes – like Hubble
• Now they are doing
James Webb SST
© 2013 ripplerock Dan Brown @KanbanDan

23. …With Supreme Excellence
• Not just about showing off…
• Focus on QUALITY!
• Post launch bugs mean something different to
NASA
• Remember the fuss about Hubble’s focus?
• James Webb will be out of reach of humans
© 2013 ripplerock Dan Brown @KanbanDan

24. What about us?
• Isn’t everything Safe to Fail?
• Yes and No.
• Yes before launch, No after launch.
• There are situations where the blue screen of
death isn’t just a phrase…
• But even when it’s not, fixing
bugs in production is the most
expensive place
© 2013 ripplerock Dan Brown @KanbanDan

25. If you love it, let it go…
• One of the key Kanban lessons:
• If you focus on Throughput,
quality drops, but then what?
• Bugs, Technical debt, slow throughput
25
Throughput Tech Debt Bugs
20
15
10
5
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
-5
(Faked exaggerated data – to illustrate the point)
© 2013 ripplerock Dan Brown @KanbanDan

26. With a quality focus…
• Focus on Quality what happens?
• Bug counts & Tech debt drop
• What happens to throughput?
25
Throughput Tech Debt Bugs
20
15
10
5
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
(Faked exaggerated data – to illustrate the point)
© 2013 ripplerock Dan Brown @KanbanDan

27. How did we get there
• By finishing ‘one small step’ at a time
• NASA started manned space flight with
Mercury
• Gemini was about learning how to go to the
moon
– 2 weeks in space for the first time
– Docking spacecraft
• Then came Apollo
© 2013 ripplerock Dan Brown @KanbanDan

28. Apollo 1 landed on the moon – right?
• Not quite
• Apollo 8 – round the moon
• Apollo 9 – test out the LEM
• Apollo 10 – drop the LEM
within 9 miles of the moon
• Apollo 11 –
– one small step…
© 2013 ripplerock Dan Brown @KanbanDan

29. Incremental steps
• They did it by doing it.
• The POC was real
launches with real
Validated Learning
• Each step moved NASA
forward and enabled the
next step
• The Moonshot started
with Wernher Von Braun
and the V2!
© 2013 ripplerock Dan Brown @KanbanDan

30. What can we learn?
• If NASA can limit WIP, so can we all
• Even the biggest of big bangs can be delivered
incrementally
• Validated Learning leads to success
• Tackle Risk by using
Collaborative Experimentation
© 2013 ripplerock Dan Brown @KanbanDan

31. My Challenge
• “Estimates inform us when things will finish”
– Only when things aren’t complex…
– Predictability based on real metrics is much better
• Kanban uses difficult maths
– Simple maths gets you most of the value
• You can’t limit WIP in big organisations
– If NASA can – so can we
– What is really stopping us?
• Validated learning doesn’t deliver anything
– It gets us through to where we need to be
© 2013 ripplerock Dan Brown @KanbanDan

32. Any Questions?
© 2013 ripplerock Dan Brown @KanbanDan