!e needs rewrite

Elo rating is a system that measures the skill level of players in games like chess, based on their wins and losses against other players. It was invented by a Hungarian-American physicist named Arpad Elo

The basic idea of Elo rating is that each player has a number that represents their skill. The higher the number, the better the player. When two players play a game, the system predicts the outcome based on their ratings. The player with the higher rating is expected to win more often than the player with the lower rating. If the outcome matches the prediction, the ratings of both players stay the same or change slightly. If the outcome is different from the prediction, the ratings of both players change more significantly. The winner gains some points and the loser loses some points. The amount of points depends on how big the difference between their ratings was and how likely the outcome was.

For example, if a player with a rating of 1500 plays against a player with a rating of 1400, the system expects the first player to win about 64% of the time. If the first player wins, they gain about 10 points and the second player loses about 10 points. If the second player wins, they gain about 26 points and the first player loses about 26 points. If they draw, they both gain or lose about 8 points.

The Elo rating system is used in many games and sports, such as chess, go, soccer, basketball, etc. It helps to rank players and teams, match them with opponents of similar skill levels, and measure their performance over time.

see also -

pairwise comparison facemash, hot or not