Mistake-Proofing for Operators: The Zqc System - Paperbackby Productivity Press Development Team (Author) The Zero Quality Control System (ZQC) is a mistake proofing approach that prevents defects by monitoring processing conditions at the source and correcting errors that cause defects. Since it is human nature to make mistakes, ZQC does not blame people for errors, but instead finds ways to keep errors from becoming defects. In this breakthrough approach, mistake proofing devices called poka yoke are used