How? I dont know whether this information has ever been compiled. Brute force method, I suspect:
1) Collect ranking lists for all the years you can find.
2) determine the ages of players, and compare to the ranking.
3) Compare age with ranking.
I suspect answer will be in low twenties, or perhaps high teens...
In another disscussion someone mentioned that Nigel Short is ranked 44th and he is 44 years of age. I thought it might be interesting to find out who was the youngest person whose age matched their ranking. I'm talking about say, FIDE top rankings, or USCF, etc.
Perhaps also, who was the youngest person whose age was greater than their rank?
How might one find out this information?