| Entrance | What she checks | The Question Asked |
| Gage Linearity | Does the instrument measure the correct value? | On a calibrated part, does the average of the measurements fall on the true value? |
| Measures | Is the instrument reproducible? | Two operators, two measurements—do they yield the same result? |
| Attribute Gage R&R | Is a visual inspection reliable? | Do two referees judge "OK" and "KO" the same way? |
| Linearity | Is the instrument in tune across its entire range? | Is the error the same at the bottom and top of the range? |
| List | — | Find and compare all registered studies. |
💡 The first four studies address different questions and cannot be replaced. An instrument can be perfectly reproducible and yet be off by 2 mm: R&R won't detect that, but pitch accuracy will.