A mistake-proofing device is any mechanism that either prevents a mistake from being made or makes the mistake obvious at a glance. Most mistake-proofing devices are physical objects which can be photographed. The ability to find mistakes at a glance is essential because, as Shingo writes, "The causes of defects lie in worker errors, and defects are the results of neglecting those errors. It follows that mistakes will not turn into defects if worker errors are discovered and eliminated beforehand."
In this webinar, Dr. John Grout discusses: