A crossed gage R&R study is an experiment that is used to estimate how much of total process variation is due to measurement system variation. Total process variation consists of part-to-part variation plus measurement system variation. Measurement system variation can further be broken down into:
Repeatability: Variation due to the measuring device or the variation observed when the same operator measures the same item repeatedly with the same device.
Reproducibility: Variation due to the measuring system or the variation observed when different operator measures the same item using the same device.