Poka-Yoke: Achieving Zero Defects

Achieving Zero Defects by Respecting Human Nature

Shigeo Shingo of the Toyota Motor Works had a revelation: Mistakes are part of human nature and are unavoidable, but defects arising from mistakes are 100 percent preventable!

Thus began the technique of mistake-proofing, or Poka-Yoke, as a countermeasure to defects. Borrowing from the military practice of fail-safing, Shingo developed this process to “respect human nature’ rather than punish it.

Yet most legacy quality systems that discourage reporting of defects for fear of reprisal and corrective action that suggests an employee “be careful” or “receive additional training” miss Dr. Shingo’s point altogether. As a result, mistake-proofing is the least employed best practice of Lean. According to Bruce Hamilton, President of GBMP, “Because employees fear that they will be punished if they report defects, they keep problems to themselves.” These opportunities for improvement are endless, but are virtually invisible to management.

Companies able to create an environment of trust that respects human nature report that Poka-Yoke is the most creative and empowering tool in the Lean arsenal. In this light-hearted look at mistake-proofing, Bruce outlines, through a series of vignettes and exercises, the steps that any enterprise can take to create a mistake-proof culture to unlock the power of employee creativity to reduce defects to zero!