In chess, how does the rating system work?

Question

After I win or lose the points goes up or down. It varies. Is there a formula? I notice for newer players points goes up or down in the 20s.

Answer 1

Short Answer:

Your rating goes up more by beating players with a higher rating than you. You were supposed to lose, so here's a reward... maybe you're better than the system thinks.

Your rating goes down more by losing to players with a lower rating than you. You were supposed to win, maybe you're not as good as your previous rating indicated.

Your rating will probably stay the same if you beat someone with a much lower rating than you. Quit picking on the little guys.

New players see their ratings fluctuate wildly while the system tries to get an understanding of what their rating should be.


Long answer:

It depends on what organization is doing the ratings. FIDE, USCF, CFC, Yahoo!, FICS, etc all have different ways of calculating a rating. Most are based on the ELO system which you can read about on wikipedia (see sources.)

The way the chess circuit works, it would be impossible to create a league with standings like the NBA or NHL. There are too many individual players and literally hundreds of tournaments going on every day. You can't rank people based on number of wins or even winning percentage as you may play your buddy ten times every night and beat him every time, but that isn't representative of your ability compared to anyone else. Chess needed a different type of ranking system that judged your performance relative to the people you play.

Essentially when you join a chess organization for the first time, they have no idea how good you are. You are given what is called a "Provisional Rating" for your first 24 games (varies by organization) which is basically a very rough estimate of your ability. The formula used to calculate a Provisional Rating is different from that of an Established Rating, meaning players with Provisional Ratings will see their ratings fluctuate considerably from game to game. Basically the formula is gathering more data points (the games you play) to get a better idea of how good you are compared to those you have played.

Each organization uses a different formula, but usually a provisional rating is a function of the average ratings of everyone you've played compared to your winning percentage in those games. If the average ratings of all your opponents is 1437 and you have a 10-10 win/loss record, your rating should be around 1437. If your record is 9-10-1, your rating should be slightly under 1437. If your record is 17-3, your rating should be considerably higher than 1437.

As the theory goes, after you play 24 games, the rating you have is a pretty good estimate of your ability. Your rating is no longer "provisional" and a different formula is used to calculate your rating from game to game.

Basically, how many points you can win or lose in a game is determined by the difference between your and your opponents ratings. If you are rated 1800 and your opponent is rated 1400, you are expected to win so if you do, your rating would go up only slightly (if at all) but if you lose, your rating would drop quite a bit. Though once your rating is "established" (ie, no longer provisional) there is a cap (around 32 if I recall) of how many points you can gain or lose in any given game.

When players have closer ratings, the result is more uncertain. If you win your rating would go up, but if you lose your rating would go down by about the same amount.

I hope that makes sense. I tried to include some reasons behind the formulae. For specific information, check the Web site of the organization you belong to (ie, Yahoo help system.)

Answer 2

Rating System: basically, a ladder system is used. By beating players you 'go up' and losing you 'go down' - simple really! See link below?

Answer 3

Wow. Mathematician Arpad Elo revolutionized the game by introducing ratings. It is complicared. Perhaps Wikipedia can describe it.