Mistakeproofing

Mistakeproofing, also known by the Japanese term poka-yoke, is a concept in quality management that aims to prevent human error from leading to defects by designing processes, equipment, and systems so that mistakes are either impossible to make or immediately detectable.

It originated in the Toyota Production System in the 1960s and was popularized by Shigeo Shingo. The goal is to reduce reliance on inspection and training by building error-prevention into the design of products and processes.

Techniques fall generally into two categories: preventing errors before they occur and quickly catching them when they do. Examples include forcing functions that prevent incorrect assembly, fail-safes and interlocks, visual or tactile cues (colors, notches), checklists, standard work, jig- and fixture-based guides, and alarms or stop signals.

Applications span manufacturing, service delivery, and software interfaces, including assembly lines, medical devices, and consumer products. Benefits include defect reduction, lower training burden, and improved safety; limitations include higher initial costs, ongoing maintenance, and potential nuisance alarms or a false sense of security.

Mistakeproofing complements broader quality-management and lean initiatives, such as standardization and mistake-proof design, and is not a substitute for root-cause analysis or systemic improvements.