Proxy (statistics)
VARIABLE USED IN STATISTICS AND EXPERIMENTAL DESIGN: NOT IN ITSELF DIRECTLY RELEVANT, BUT THAT SERVES IN PLACE OF AN UNOBSERVABLE OR IMMEASURABLE VARIABLE
Proxy variable; Proxy measurement; Proxy measure
In statistics, a proxy or proxy variable is a variable that is not in itself directly relevant, but that serves in place of an unobservable or immeasurable variable.Upton, G.