Module 3 · Lesson 10 of 17
Continuous Gage R&R concepts
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Learning objectives
- Design a crossed continuous Gage R&R study.
- Interpret variance components and % study variation.
- Improve the measurement system when it dominates variation.
What the study estimates
A crossed Gage R&R separates observed variation into part-to-part, repeatability and reproducibility components. The goal is to know how much of what you ‘see’ is really the process versus the gauge.
Free spreadsheets can compute the standard variance components; the guideline is <10% of study variation is acceptable, 10–30% marginal, >30% unacceptable.
Garment-factory example
Three technicians measure ten polos twice each for chest width using the approved fixture, with prior results concealed and order randomised.
Method
- Select 10 parts that span the process range.
- Use 2–3 trained appraisers and 2–3 randomised trials.
- Blind each trial from previous results.
- Compute components and % study variation and act on the largest.
Common mistakes
- Using consecutive identical parts.
- Letting appraisers see prior readings.
Knowledge check
Pick one answer per question. Explanations appear after you submit.
1. A crossed R&R needs parts that:
2. Blinding trials prevents:
Author: NOSK.life · Last reviewed: 2026-07-21