10. where special causes can reoccur. McDonald's designed system to be mistake-proofing and easy to learn. In the short run, the cost of quality may be reduced by sorting out defects. Where Mistake-Proofing does NOT work well 1. Production rate is very fast.
Shifts occur more rapidly than they can be responded to.
Self-checks when control charts are used effectively. 2. as production rate speeds up, cost of momentary delays due to inspection become very costly. If true, you got bigger problems to worry about 4. Despite what you'll probably read if you look into poka-yoke further, SPC is better for managing variance. Poka-yoke is better for mistakes.