Mistake-proofing (poka-yoke) on the line
Why people make mistakes even when they're careful, and how mistake-proofing stops a mistake becoming a defect: control versus warning devices, the contact, fixed-value and motion-step methods, checking devices at start-up with known-bad challenge parts, and what an operator does when a device fails its check, gets bypassed or alarms for no clear reason.
- Level
- Intermediate
- Length
- About 50 minutes
- Contents
- 4 lessons · 1 video · final exam
- Status
- Published · updated 1 Oct 2026
Skills you'll practise
- Distinguish a mistake (error) from a defect, and explain why mistake-proofing targets the mistake
- Classify an error-proofing device as control or warning type, and by method: contact, fixed-value or motion-step
- Carry out and record a start-of-shift verification using known-bad challenge parts
- Respond correctly when a device fails verification: stop, contain output back to the last good verification, and escalate
- Explain why operators never bypass, tape over or adjust an error-proofing device, and how to report nuisance alarms
Course outline
- 1.Mistake-proofing on the lineVideo · 3 min
- 2.Mistakes, defects and why careful people still slipLesson · 15 min
- 3.Types and methods of error-proofingLesson · 17 min
- 4.Verifying devices at start-upLesson · 17 min
- 5.Bypasses, nuisance alarms and authorityLesson · 14 min
- 6.Mistake-proofing (poka-yoke) on the line: knowledge checkKnowledge check · 21 questions
- 7.Mistake-proofing (poka-yoke) on the line: practical exerciseKnowledge check · 1 question
- 8.Final exam9 questions · passing it completes the course, so people who already know the material can test out
Sources it draws on
The lessons and questions are written from these references, so learners can go back to the original.
- Wikipedia: Poka-yoke (Shigeo Shingo; contact, fixed-value and motion-step methods; warning vs control poka-yoke)
- Shingo, S. (1986). Zero Quality Control: Source Inspection and the Poka-yoke System. Productivity Press (as cited by the Wikipedia article)
- Your site's quality manual, control plans, drawings, work instructions and procedures (these govern)
See it with your own jobs and topics
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