Gage R&R

Gage R&R, which stands for gage 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. See Gage R&R tools.

There's an excellent post on the discussion forum by Stephen Curtis describing Gage R&R:

"Gage R&R is intended to be a study to measure the measurement error in measurement systems."