the degree to which the scores of a patient-reported outcome (PRO) instrument (or any measurement tool) correspond with those from an established “gold standard” that measures the same concept. High criterion validity indicates that the instrument produces results consistent with the reference standard. Because most PROs lack a true gold standard, criterion validity is often difficult or impossible to assess directly.
Example
A new depression questionnaire is developed for primary care. To test criterion validity, researchers compare its scores to those from the Hamilton Depression Rating Scale (considered a gold standard in research). A strong positive correlation between the two sets of scores would support the new instrument’s criterion validity.