Ratings

Standard play games

Requirements for a game to be rated

For a game to be rated, we take a look at a player with the highest rating in the tournament. We assume that the game lasts 60 moves

• 2200 or greater: 120 minutes for each player
• 1600 or greater: 90 minutes for each player
• < 1600: 60 minutes for each player

For games with multiple time controls, this is 40 minutes to the first time control.

• You can only have at most 12 hours of play in one day
• Tournaments should not last more than 90 days (without approval). These should be reported monthly

Getting the first rating

• Play 5 games against rated opposition. These games should take place within 26 months (2 and a bit years)
• You must score at least \(\frac{1}{2}\) pts in the first performance. For example, if you played a tournament 1 with 3 rounds and tournament 2 with 2 rounds, if you win \(\frac{1}{2}\) points in the first tournament you are eligible for a rating. If you instead won 0 points in the first tournament, you're not eligible.
• Your rating must be 1000 or more.

Round Robins

• A third of players must be rated with a minimum of 4 rounds
• Double round event needs at least 6 players
• Unrated players who score 0 are ignored

Swiss tournaments

• Unrated players must score for their games to count (even if they only play 1 game)
• Rated players must play against rated opponents to count for a rating

Matches

• When the match is decided (e.g. 5pts - 3pts in a 9 round game), the further games won't count (such as the last 9th round)
• Matches against players which are unrated do not count for ratings

How to calculate ratings

You start counting games from the first game where you get a point (1 or \(\frac{1}{2}\)). For example, if a player plays their first game and gets 0, we ignore it.

In a swiss of team tournament, the rating is calculated based on the average of the opponents and the percentage score.

If the score is 50% then their rating is equal to the opponent's average. If more than 50%, then it's the opponent average + 20 for each half point scored above 50%. If less than 50, then table lookup.

Example

Player opponents average is 1800. They won 4/8 games, that means they've won 50%. Therefore their rating for the tournament is 1800. If they won 5/8, rating is 1800 + 2 * 20 = 1840. If scores 2/8, that's 0.25 - look it up in the table, it's -193. Their rating is 1800 - 193

This system punishes you for losing 50% or more of your games.

Players with ratings already

exp is the % that you'll expect to win if you played 100 games

Rating lists

Rating list appears monthly. Deadlines are 3 days before the end of the month.

If an unrated player gets a new rating mid-tournament (during a change of months), you leave the original rating instead of the new one. Always go with the rating the beginning of the tournament

K Factors (AKA Development coefficient)

• K = 40 for players who are new to the rating list until they played 30 games.
• K = 20 for players with rating < 2400
• K = 10 when their rating is 2400. Even if the rating drops below 2400, the K factor remains for life!
• K = 40 for all players until their 18th birthday, as long as their rating remains under 2300.

Exceptions to this:

• (Number of games for a player (in a month)) * (K factor) should never exceed 700. If so, we reduce your K factor. K factors can only be whole numbers