Universal Principles of Design, Updated and Expanded Third Edition

142 Poka-Yoke

A thing designed to prevent defects and errors.

Poka-yoke is a Japanese term that means mistake-proofing and broadly refers to any mechanism or process that prevents design defects. The concept was developed as part of the Toyota Production System to prevent defects — the notion being that human errors are inevitable but defects can be detected and corrected before they reach the customer. For example, the feature in many word processors that automatically highlights misspelled words is a poka-yoke.1

The systematic application of poka-yoke involves four-steps: (1) identifying defects, which are defined broadly as any cause of customer dissatisfaction, (2) identifying the causes of those defects, focusing on root versus proximal ...