Poka-yoke (ポカヨケ) is a Japanese term that means “fail-safing” or “mistake-proofing”. A poka-yoke is any mechanism in a lean manufacturing process that helps an equipment operator avoid (yokeru) mistakes (poka). Its purpose is to eliminate product defects by preventing, correcting, or drawing attention to human errors as they occur.
Not just handy for manufacturing processes, this idea applies very easily to any kind of designed object. How can we make what we design not only easy to use, but as difficult as possible to mis-use? (It’s worth noting that this principle was originally described as baka-yoke, i.e. idiot-proof, unfairly placing the blame on the user instead of the design)