Many factories visualize defect data, yet the numbers often don’t make sense. In several plants I supported, the same production batch showed different defect rates depending on the inspector—2% by an expert versus 8% by others. The issue wasn’t product quality but human behavior shaped by inadequate KPIs. When inspectors are evaluated by “how many items they check,” speed is prioritized, judgment becomes inconsistent, and defect data becomes unreliable. This leads not only t