2. Meaning of POKAYOKE
• Pronounced as POH-KAH-YOH-KAY
• YOKERU AVOIDE
• POKA MISTAKE
Coined in Japan during the 1960s by as part of the Toyota Production
System.
3. Idea of POKAYOKE
• Shigeo-Shingo invented the Japanese concept called
POKA-YOKE
• The essential idea of poka-yoke is to design your process
so that mistake are impossible or at least easily detected
and corrected .
4. What is Error?
Deviation from what is correct,
right, or true.
How to prevent error
Old way :- Scold people,
reprimand worker, retrain
them, tell them to be careful,
tell them to pay attention…..
New way:-Remove the
opportunity of error, improve
the process, make wrong
action more difficult, training
and motivation, make easier
to discover the mistake
5. What is Mistake Proofing?
Mistake proofing is the activity of awareness, detection, and
prevention of mistakes
• Prevention
• Detection
• Awareness
7. First Poka-Yoke Device
• In the new approach a small plate is placed in front of
box and the worker’s first task is to take two springs our
of the box and place them in the plate
• Then the worker assemble the switch if any spring
remain on the plate, then worker knows that he or she
forgotten to insert it.
Empty plate
8. Case study of Empty Soap Box
• The cosmetic company in Japan received a complaint that a consumer had
bought a soap box that was empty.
• Management asked its engineers to solve the problem.
• The engineers worked hard to devise an X-ray machine with high-
resolution monitors manned by two people to watch all the soap boxes
that passed through the line to make sure they were not empty.
• No doubt, they worked hard, and they worked fast but they spent
whoopee amount to do so.
• But when a workman was posed with the same problem, did not get into
complications of X-rays, etc but instead came out with another
solution.
• He bought a strong industrial electric fan and pointed it at the
assembly line. He switched the fan on, and as each soap box passed the fan,
it simply blew the empty boxes out of the line.
• Moral:-Always look for simple solutions. Prepare the simplest possible
solution that solves the problem.
9. Poka-Yoke in Everyday Household
Products
•Micro-wave oven does not work until the door is shut.
•Washing machines only start when the door is closed and
cannot be opened until the cycle is over.
Electric plugs have an earth pin that is longer than the other
pins and is the first to make contact with the socket. The
protective shield of the neutral and earth sockets are then
opened safely.
Elevator doors have a sensor that causes them to open when
there is an obstruction-this prevents injury to someone trying to
enter as the doors are closing.
Circuit breakers in the home electrical system prevent electrical
overloads.
11. Defect Prevention
• Defect prevention is the most important activity in SDLC
• Many software defect can be prevented in design phase itself
• QA team can help to prevent these defects by reviewing SRS or
any wireframe
• Defect can be identified in coding phase during unit testing and
prevented from carrying to later stage
12. Defect Detection
• Defect detection is the most common task for testing teams
• QA team have various approaches and strategies for
executing test case effectively
• Defects are detected by many other testing methods like
smoke and exploratory testing.
13. Qualities of Good POKAYOKE
System
• Simple to create and maintain
• Designed early in SDLC
• Accurate to find issues when they occur
• Avoid common mistakes
• It should be part of software design and coding process.
14. Recommendations for Creating Good
Software Poka-Yoke
• Think simple
• Think specified
• Think early
• Think responsive
18. Adopt a Poka-Yoke Mindset While
Testing
Fig 1 – A simple file uploader
Fig 2- You discover that they can only upload certain file
types
Fig 3- Instructions added specifying the supported file
19. Thank You
For Your Attention
You can find me at:
akshay.kulkarni@suneratech.com
