In short: Measurement system analysis (MSA) evaluates how much variation comes from the measurement system itself. A Gage R&R study quantifies repeatability (equipment) and reproducibility (appraisers).
What is a Gage R&R study?
Several appraisers measure the same parts several times. Statistical analysis separates measurement variation from part variation.
How are results interpreted?
Commonly used guidelines treat measurement variation under 10% of total variation as acceptable, 10–30% as possibly acceptable depending on application, and over 30% as unacceptable.
Key takeaways
- Check measurement systems before analysing processes.
- Separate repeatability from reproducibility.
- Improve gauges or methods when variation is too high.
Frequently asked questions
What is repeatability?
Variation when the same person measures the same part repeatedly with the same instrument.
What is reproducibility?
Variation between different appraisers measuring the same parts.
Is MSA required by IATF 16949?
Yes, MSA studies are required for measurement systems referenced in the control plan.