Hungarian-born US physicist and statistician who, in the early 1960’s, developed a mathematically sound and universally accepted (1970) rating system for chess players.
Elo was a professor of physics at Marquette University in Milwaukee and was a good chess amateur many times Wisconsin State chess champion from 1935 to 1961.
He spent 20 years developing, validating, and popularizing his rating system, which was accepted by FIDE in 1970 for international use.