These are the questions Compass asks for this practice, and the levels it scores you against.
Systematically cataloguing which process steps produce errors and what type of mistake drives each one.
How do you identify where errors enter the process?
Level 1 → 5World class at level 4
- We find errors at final inspection or from customer complaints only
- We know rough areas from experience but have no structured list
- We use defect data and walk the process to identify error-prone steps
- We map every process step against its most likely mistake type and causeWorld class
- Structured error source analysis is embedded in every new process launch and change review
Selecting and implementing physical or digital mechanisms that prevent or detect specific errors.
How do you respond when an error source is identified?
Level 1 → 5World class at level 4
- We retrain the operator or add an inspection step
- We sometimes add a jig or fixture but it depends on the engineer's initiative
- We apply error-proofing devices to our highest-impact defect sources
- For every identified error source we specify a prevention or detection device before closing the actionWorld class
- Formal error-proofing reviews are part of our process design gate; devices are validated before production release
Confirming that installed error-proofing devices actually prevent or detect the target mistake.
How do you confirm that an error-proofing device is working?
Level 1 → 5World class at level 4
- We assume it works if defects drop — no formal check
- We monitor defect rates after installation for a few weeks
- We run a deliberate failure test — intentionally introduce the error to verify the device catches it
- Each device has a documented validation test and a pass/fail criterion; we re-test periodicallyWorld class
- Device effectiveness is tracked by actual defect-escape rate; devices with escapes are redesigned, not just re-trained around
