Notes on Ratings
Under the Elo ratings system, the winner of a game gains a number of ratings points and the losing player loses the same number. The number of points won or lost depends on the difference between the ratings of the two players; a player will gain more points by beating a higher-rated player than by beating a lower-rated player.

Where games have been completed, the chart above shows the actual number of ratings points passed from the loser to the winner. Where games are unfinished, two numbers are shown in the form A/B. A is the number of points to be transferred if the player in the row wins and B is the number of points if the player in the column wins.

For example

	Mildred Elo 5051	If Joe wins he will gain 9.5 rating points from Mildred but if Mildred wins she will gain 14.5 rating points from Joe. Mildred stands to earn more than Joe from winning the game because Joe is the higher rated player and is expected to win more often.
Joe Elo 5123	E: 9.5 / 14.5

In the case of a draw, the lower rated player wins points from the higher rated player, but fewer points than if he or she had won the game.

The value of each game is based on the players' rating at the start of each round. At the end of the round, the points won and lost on each game are added up and the players' rating are adjusted and rounded to the nearest whole number for the next round.

The difference in two players' Elo ratings implies an expectation of how often each of them will win when playing each other. Under the system we use:

• a player with a rating of 400 more than her opponent is ten times as likely to win
• a player with a rating 120 more than his opponent is expected to win two times out of three
• a player with a rating 75 more than her opponent is expected to win three times out five.