What is repeatability and how is it measured in a gage R & R study? The repeatability measured by a gage R & R study refers to the variability in measurement which results when one individual measures one part using one gage. In other words, when one operator measures one part using one gage again and again, the resulting changes in measurement are due to an error that is occurring within the equipment. While infinitesimal repeatability issues are going to be expected, a gage R & R study can root out more serious inconsistencies. Testing repeatability is an important part of gage R & R studies, and it is what tells you that your gage is imprecise and requires attention.