Mistake-proofing, or its Japanese equivalent poka-yoke (pronounced PO-ka yo-KAY)(also known as Fool-proofing, error-proofing, and fail-safing), is the use of any automatic device or method that either makes it impossible for an error to occur or makes the error immediately obvious once it has occurred. It is a common process analysis tool.

Mistake-Proofing is about adding techniques to prevent defects and detect defects as soon as possible, if one does occur.

Poka-Yoke is often used as a synonymous term but its meaning is to eliminate product defects by preventing human errors (that are unintentional). The concept was first put to widespread use by Shigeo Shingo within the Toyota Production System (TPS).

When an error can not practically be 100% prevented or detected, then the next best option is to try to reduce the severity of the error and defect.

When to use Mistake-Proofing

  • When a process step has been identified where human error can cause mistakes or defects to occur, especially in processes that rely on the worker’s attention, skill, or experience.
  • In a service process, where the customer can make an error which affects the output.
  • At a hand-off step in a process, when output (or for service processes, the customer) is transferred to another worker.
  • When a minor error early in the process causes major problems later in the process.
  • When the consequences of an error are expensive or dangerous.


ASQ. “Quality Glossary Definition: Mistake proofing.” https://asq.org/quality-resources/mistake-proofing

Six Sigma Material. “Mistake-Proofing (Poka-Yoke).” https://www.six-sigma-material.com/Mistake-Proofing.html