Mistake-Proofing Must Be Inexpensive

Each undetected error occurs roughly once in 10,000 to 100,000 operations in a production environment. Since the events rarely occur, we must generally find inexpensive solutions to prevent or control mistakes.

Mistake-Proofing Requires 100% Inspection

It is impossible to detect most mistakes with sampling inspection, and statistics cannot predict or control mistakes. However, most companies would go broke trying to perform 100% inspections with traditional inspections. Only Mistake-Proofing methods are inexpensive enough to control mistakes effectively. The operator should never have to perform a separate action to execute a Mistake-Proofing inspection since the inspection operation could be omitted, and a mistake or defect would not be detected.

Many Mistake-Proofing Devices are required

Even though each specific error is a very rare event, a wide range of mistakes can occur. World-class leaders have an estimated 12 Mistake-Proofing devices per workstation, which reflects roughly 60 seconds of takt time – or one Mistake-Proofing device for every 5 seconds of work.

Mistake-Proofing Blocks Undesired Outcomes

It is impossible to control all of the causal factors linked to mistakes, including: forgetfulness, fatigue, distraction, and so forth. Mistake-proofing intervenes to prevent the undesired action or defect.

All Mistake-Proofing Solutions Are Not Equally Effective

As illustrated by the arrows in the chart, the best Mistake-Proofing inspection prevents mistakes, rather than detecting mistakes, which in turn is better than detecting defects. A shutdown is better than a warning as a control method since warnings can be ignored, but the best control method is to control the mistake rather than a shutdown.