Factors that affect measurement system variation can be studied using the gage repeatability and reproducibility (GR&R) technique.

Measurement system variation can be characterized by location (stability, bias, linearity) and width or spread (repeatability and reproducibility).

Gage repeatability and reproducibility (GR&R) study can be applied in most manufacturing-related measurement systems. It may be used as:

• A criterion for judging new measuring equipment.
• A comparison among measuring devices.
• A means for improving performance of measuring instruments.
• A comparison for measuring equipment before and after repair.
• A required component for calculating process variation and the acceptability level for a production process.
• A measure of the need for training in how to use measuring instruments.

Excerpted from Donald W. Benbow, Ahmad K. Elshennawy, and H. Fred Walker’s The Certified Quality Technician Handbook, ASQ Quality Press, 2003, pages 116-117.