It was a Japanese manufacturing engineer named Shigeo Shingo who developed the concept that revolutionized the quality profession in Japan. Originally called “fool proofing” and later changed to “mistake proofing” and “fail safing” so employees weren’t offended, poka yoke (pronounced “poh-kah yoh-kay”) translates into English as to avoid (yokeru) inadvertent errors (poka). The result is a business that wastes less energy, time and resources doing things wrong in the future.

What Is Poka Yoke?

Poka yoke is one of the main components of Shingo’s Zero Quality Control (ZQC) system – the idea being to produce zero defective products. One way this was achieved is through the use of poka yoke; a bunch of small devices that are used to either detect or prevent defects from occurring in the first place. These poka yoke methods are simple ways to help achieve zero defects.

Who Develops Poka Yokes?

Here’s the beauty of the methods…anyone, from manager to line supervisor to line employee can develop a poka yoke. (Alright for you transaction people out there…anyone, from regional sales manager to sales associate to document specialist). All it takes is the empowerment of employees, as well as a little instruction around what makes a good poka yoke.

What Does a Poka Yoke Look Like?

Poka yoke looks different in each situation. I’ll try to present a few different scenarios for poka yoke use. Let’s take a transactional situation and analyze a few parts of it. Say, for instance, we’re at the signing of a bank loan by a lucky couple closing the mortgage on their first home.

Example 1:
The lucky couple picks up the pen to sign, but when they depress the top of the pen to extend the writing part it malfunctions because the spring is missing. A poka yoke could have prevented this situation. If all pieces of the pen were presented to the assembler in a dish, a simple poka yoke would be for the assembler to visually inspect the dish for any remaining parts once the pen was assembled. (Ok, I lied about this being only a transactional process!)

Example 2:
The lucky couple bypasses the signature part of the process because their bank is really high-technology focused. In fact, they signed a writing pad and their signature was recorded electronically. The bank also needed to collect four additional pieces of information before the entire package of information is sent to the processing department. A simple poka yoke to add to this process is to require all fields to be filled in (including the loanee signature) before allowing the form to be sent to processing. This prevents the processing department from reviewing an incomplete document, sending back to the loan department, delaying the processing of paperwork…you get the idea.

Example 3:
Once the complete paperwork is submitted to the processing department and it is printed, it then needs to be filed with the city and state. In order for this to occur, papers need to be filled out (the city and state are not high-technology enabled) and attached to the form. A poka yoke used by the city is a simple check-sheet at the top of the form. This allows the person submitting the form to ensure that all additional information and payments are attached. As in example 2 above, this prevents the city/state from reviewing an incomplete document, sending back the document to the sender, delaying the processing of paperwork…again, you get the idea.


Is there any rocket science to poka yoke? I don’t think so either. So what’s the big deal? Well, the big deal involves execution within your business. Bright ideas are a dime a dozen, it’s the execution that’s the hard part. First, you need to educate your workforce on the concept of poka yoke (call it mistake proofing for ease). Second, you need to empower your employees to make a bunch of small improvements to their processes – continuously. What you will end up with a business that wastes less energy, time and resources doing things wrong in the future.

User Test – Real World Scenario

I was recently reading a newspaper article entitled “Surgeon operates on wrong side of man’s head.” An excerpt is below:

Providence, Rhode Island, USA – A surgeon at Rhode Island Hospital operated on the wrong side of a man’s brain after a CAT scan was placed the wrong way round on an X-ray viewing box, the hospital told the state Health Department.

The patient had bleeding on the right side of his brain but the reversed scan made it look as if the bleeding was on the left. In addition, the patient’s incision site had not been marked with a pen, as recommended by error-prevention experts.

You’re probably thinking the same thing as me…WOW, how could this happen with all the procedures, mistake proofing, quality systems, etc.? It just amazes me. The good news is that the patient lived after the doctor repeated the procedure on the right side and the blood was drained. It turns out that wrong-side surgery tops a list of 27 serious, preventable events says the National Quality Forum, which promotes a strategy for measuring healthcare quality.

So what can we do about it? Well, let’s help the medical system out. Post your thoughts in the comments section below.

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