The phrase "rough proxy" means an approximate or close estimation of something, even though it may not be completely accurate or precise. Full definition
So analysts rely on rough proxies for foreign ownership. (calmatters.org)
The measures used in the NEPC report — whether schools make AYP, state accountability system ratings, the percentage of students that score proficient on state tests, and high - school graduation rates — are at best rough proxies for the quality of education provided by any school. (educationnext.org)
(Jean Buzby of the USDA said in an email that food supply is a commonly used rough proxy for food consumption.) (health.com)