# Poka-Yoke **URL:** https://kaizumi.com/dictionary/poka-yoke **Description:** Poka-yoke is mistake-proofing - designing processes and devices to prevent errors or make them immediately obvious. **Japanese:** ポカヨケ (poka-yoke) — "mistake-proofing, error prevention" **Category:** lean-tools **Tags:** quality, foundational ## Definition Poka-yoke, coined by Shigeo Shingo, means "mistake-proofing" or "error prevention." It encompasses simple devices or design features that either prevent errors from occurring or make errors immediately obvious so they can be corrected. Poka-yoke recognizes that humans will make mistakes—especially in repetitive work or under stress—and designs systems that account for human fallibility rather than relying on attention and effort alone. The most effective poka-yoke makes errors impossible by design; the next best makes errors immediately detectable. ## Examples ### Manufacturing > A connector designed to fit only in the correct orientation is poka-yoke—assembly errors are impossible because incorrect assembly is physically prevented. Similarly, fixtures that won't accept parts loaded backward prevent orientation errors. ### Healthcare > Color-coded tubing connections that only fit corresponding ports prevent dangerous cross-connections. A medication dispensing system that requires barcode verification before release catches wrong-drug errors before administration. ### Administrative > A digital form that won't submit without required fields prevents incomplete submissions. A system that flags mathematical inconsistencies (expenses not matching receipts) catches errors before they propagate. ## Key Points - Prevention (error impossible) is better than detection (error visible) - Poka-yoke should be simple, reliable, and close to the point of error - People make mistakes; good systems account for human fallibility - Poka-yoke often emerges from analyzing past errors ## Common Misconceptions **Poka-yoke is expensive technology.** Many effective poka-yoke devices are simple and inexpensive—a guide, a color code, an asymmetric design. Creativity matters more than budget. **Poka-yoke replaces training.** Training teaches correct methods; poka-yoke prevents errors when correct methods aren't followed. Both are needed—poka-yoke is backup for human fallibility, not replacement for competence. ## Watch It Happen Error-proofing is a place as much as a mechanism. In the factory simulation the reject bay sits at S2, the station that fits the pedals — not at final inspection. A wrongly fitted pedal fails the torque check and the fixture will not release the bike, so it goes down a chute still half-built. Everything it is missing is work that never got wasted on a bike that was going to be taken apart again. ## See Also - [Jidoka](/dictionary/jidoka) - The broader principle poka-yoke supports - [Poka-yoke in manufacturing](/guides/poka-yoke) - Worked examples of contact, fixed-value and motion-step devices Source: https://kaizumi.com/dictionary/poka-yoke Licence: free to quote and cite with attribution to Kaizumi.