A look at 5 forms of Mistake Proofing with visual examples from everyday life.

1. Mistake Proofing
an exploration of 5 forms with examples
by Tom Curtis

2. • Created July 2010 by Tom Curtis
• All Pictures take by Author
• Blog: www.onimproving.blogspot.com
• Other Presentations: Onimproving on
www.slideshare.net

3. An Introduction
Mistake Proofing is all around us whether we
recognize it or not. The purpose of this
document is to look at some of the common
ways it can be deployed and examples to help
begin to recognize and start to employ in our
spheres. This does not seek to be the last word,
but hopefully a door to seeing mistake
proofing in the world around us.
--Tom Curtis 2010

4. Forms of Mistake Proofing
Preventing
Pausing
Notifying
Minimizing
Guiding
May overlap or be used in combination

5. Preventing
In some cases a mistake can be prevented.
This may include use of shape or size or
function. Classic examples in this space
include the different size of the diesel and
unleaded gas nozzles, or something that can
only fit in one way. This is sometimes
called poka-yoke. This form is most often
associated as mistake proofing.

6. Different
Size Hook
Preventing

7. Inside
Trunk
Release
Preventing

8. Protects
Against
Balls
Preventing

9. Key
Required
to Adjust
Preventing

10. Newspapers
and no
Bottles
Preventing

11. No Lost
Tickets
Preventing

12. Helps Fight
Unhappiness
Preventing

13. Automatically
Locks
Preventing

14. No Hook
Hanger
Preventing

15. Pausing
Pausing or delaying techniques do not fully
prevent a mistake occurring, but rather force
an individual or group to stop and overcome
some hurdle to proceed. An example is a
computer program that asks “Are you sure?”
before executing a desired command. The
goal is that in being forced to stop a mistake
may be prevented.

16. 2 Step
Process
Pausing

17. Review Before
Ballot Cast
Pausing

18. Difficult to
put in
Pocket
Pausing

19. Must Push
Twice
Pausing

20. Must Push
both
Buttons
Pausing

21. Notifying
In notifying the system or process lets us
know that something needs to be addressed,
but does not prevent us from continuing, like
in preventing or pausing forms. For this
type of proofing think of the gas light in
most cars. It lets us know that a mistake will
eventually be made (running out of gas),
but it is up to us as to whether we heed the
notice or not.

22. Gas
Needed
Soon
Notifying

23. Entering
Oncoming
Lane
Notifying

24. Helps
Proper
Setup
Notifying

25. Stay Out
Notifying

26. Minimizing
In minimizing it is realized that there may
be a mistake made, but that the damage can
be controlled. Think of a machine that shuts
down when it gets too hot. The machine does
get hot, but does not allow the motor to burn
out. There is some damage done, but the
greater damage is minimized.

27. Triggers
Turn Off
Minimizing

28. Eventually
Self Turns Off
Minimizing

29. Less Likely
to be left
on
Minimizing

30. Less
Splashing
Minimizing

31. Guiding
Guiding or suggesting is similar to
notifying, in that it does not stop the process
and is a message from the process. It differs
in that there is not a mistake that will happen
if disregarded. An example is the please wash
your hand signs for employees that you
often see in public restrooms. We are
protected if we heed, but are not punished
automatically if we do not.

32. Friendly
Restroom
Reminder
Guiding

33. Gentle
Nudge
Guiding

34. Warning of
Terrain
Ahead
Guiding

35. Reducing
Lost Cars
Guiding

36. Request for
Help
Guiding

37. Can be seen
in Case of Fire
Guiding

38. Gentle Nudge
Before Fueling
Guiding

39. Reducing
Injuries
Guiding

40. Driving Tip
Guiding

41. Strong
Suggestion
Guiding

42. Cleaning
between
Uses
Guiding

43. Request to
Refrain
Guiding