# Error-proofing

Operations · `Error-proofing` · verification: source checked

Error-proofing is a method for helping operators avoid mistakes such as choosing the wrong part, leaving out a part, or installing a part backwards. It is also called mistake-proofing, poka-yoke and baka-yoke (fool-proofing). It is applied through design features and sensing devices that prevent or detect incorrect assembly work.

## Specification

| Property | Value |
|---|---|
| Kind | methodology |

## Study notes

- Also known as mistake-proofing, poka-yoke (error-proofing) and baka-yoke (fool-proofing).
- Listed synonyms: Baka-Yoke, Mistake-Proofing, Poka-Yoke.
- One example is a product design with physical shapes that make it impossible to install parts in any orientation except the correct one.
- Another example is photocells above parts containers that stop a product moving to the next stage if the operator's hands have not broken the light to obtain the necessary parts.
- A more complex version uses photocells with additional logic to check that the right combination of parts was selected for the specific product being assembled.
- Related topics named in the document: Inspection and Jidoka.

## Sources

1. [Error-Proofing - Lean Enterprise Institute](https://www.lean.org/lexicon-terms/error-proofing/) (accessed 2026-10-25)

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