Gauge R&R, which stands for Gauge Repeatability and Reproducibility, is a statistical tool that measures the amount of variation in the measurement system arising from the measurement device and the people taking the measurement.
"Gauge R&R is intended to be a study to measure the measurement error in measurement systems."
Gauge Repeatability is the variation in the measurements obtained with one gauge when used several times by one operator while measuring the identical characteristic on the same part.
Two sources of repeatability error in the measurement system are:
1. Variation in measurements due to the gauge itself.
2. Positional variation of the part in the gauge.
Repeatability is thus also called the Equipment Variation (EV).
Gauge Reproducibility is the variation in the average of measurements made by different operators using the same gauge when measuring identical characteristic on the same part.
Reproducibility error catches the variation due to operators. It is also called the Appraiser Variation (AV).
Study to find Gauge Repeatability & Reproducibility is divided into three parts – GRR Mapping, GRR Measurement and GRR Data Analysis.