Error Proofing, Mistake Proofing, or in Japanese Poka-Yoke. 

Shigeo Shingo developed Poka-Yoke while working for Toyota.

Poka-Yoke is first and foremost the prevention of an error before it could have occurred. That is, you cannot do it wrong. It can only be done one way. A three-prong plug can only be inserted one way.

poke yoke isssp

Baring that it is next the 100% detection that an error did occur. So, if it is wrong, we absolutely know it. For example, this would be depicted in a visual and audio signal that your auto seatbelt is not connected.

And finally, it is the prevention of the defect or error from going into the next step of the process. An automatic shutdown at a manufacturing process step is one example.

Simple Steps to Implementing Error Proofing

  • Identify the defect
  • Map the process
  • Analyze the process steps. 
    • Where is the defect likely to occur?
  • Determine the root cause. What contributes to the defect?
    • Here tools such as the 5 Whys and FMEA can be useful
  • Develop and apply an error-proofing approach
  • Validate the approach works

Mistake proofing can be applied to any process regardless of the environment.

In this short video, Rich Becker of the College of American Pathologists applies it to a simple administrative task for sending out course code notifications.

You can view Rich’s video here.