An internationally accepted mathematical system for ranking chess players, created by Arpad Elo. International Grandmasters are typically in the range 2500 to 2700, world champions often over 2700. The standard deviation is 200 points. The scale is such that a player at 1800 would be expected to beat one at 1600 by the same margin as a player at 2600 against one at 2400. Many games must be played before an Elo rating can be estimated with confidence. The Elo rating is the foundation for the award of FIDE titles.