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  1. 13 Oct '10 22:19
    Can anybody explain [in simple terms] the rating system...?? One of my current opponents has: played 76, won 36, lost 30, drawn 10, won 47% and is rated 1667.
    I have: played 59, won 41, lost 12, drawn 6, won 69% and am rated 1612.

    I am not a ratings maniac and should probably just stick to playing chess, but it doesn't seem to make any sense?? If anybody has the time.....
  2. 13 Oct '10 22:24 / 1 edit
    Originally posted by Indonesia Phil
    Can anybody explain [in simple terms] the rating system...?? One of my current opponents has: played 76, won 36, lost 30, drawn 10, won 47% and is rated 1667.
    I have: played 59, won 41, lost 12, drawn 6, won 69% and am rated 1612.

    I am not a ratings maniac and should probably just stick to playing chess, but it doesn't seem to make any sense?? If anybody has the time.....
    FAQ
  3. 13 Oct '10 23:28
    What?
  4. Subscriber Paul Leggett
    Chess Librarian
    13 Oct '10 23:34
    Originally posted by Indonesia Phil
    What?
    If you put your mouse on the "FAQ" link and left click, it will take you to the section entitled "Frequently Asked Questions", which is the origin for the "FAQ" acronym.

    In that section, your question is answered.
  5. Subscriber Paul Leggett
    Chess Librarian
    13 Oct '10 23:36
    Just in case:

    How is my rating calculated?
    FAQ
    When you join, you are given a rating of 1200.

    If you enter into a rated game, your rating will be recalculated on its completion so long as at least two moves have been made by each player.

    Note: Until you have completed 20 games your rating may go down even when you win a game!

    Until you complete 20 games, you will have a provisional rating. This rating is calculated as the average of all the games you have played. Each game is scored as being your opponent's rating (for a draw), your opponent's rating plus 400 (for a win), or your opponent's rating minus 400 (for a loss). If your opponent is also on a provisional rating, then the 400s above become 200s. If your opponent has played fewer than five games then their rating is treated as 1200 when calculating your rating.

    Players are rated using the following formula:

    New Rating = Old Rating + K * (Score - Win Expectancy)

    K is a constant (32 for 0-2099, 24 for 2100-2399, 16 for 2400 and above)

    Score is 1 for a win, 0.5 for a draw and 0 for a loss.

    The Win Expectancy is calculated using the following formula :

    Win Expectancy = 1 / (10^((OpponentRating-YourRating)/400)+1)

    The Win Expectancy is used in the rating calculation but is interesting on its own. For example, the calculation below is for a rating difference of 200. This shows that if you have a rating 200 points higher than another player, you can expect to beat them, on average, three times for each four games played.

    Win Expectancy = 1 / (10^(-200/400)+1) = 0.76

    Note: ^ = "to the power of", e.g. 2^3=8.

    If you have a non-provisional rating and you play a provisional-rated player, then you receive (or lose) only half the number of rating points you would normally. If the provisionally-rated player has played fewer than five games, then their rating is treated as 1200 when calculating your rating.
  6. Standard member wormwood
    If Theres Hell Below
    14 Oct '10 00:57
    Originally posted by Indonesia Phil
    Can anybody explain [in simple terms] the rating system...?? One of my current opponents has: played 76, won 36, lost 30, drawn 10, won 47% and is rated 1667.
    I have: played 59, won 41, lost 12, drawn 6, won 69% and am rated 1612.

    I am not a ratings maniac and should probably just stick to playing chess, but it doesn't seem to make any sense?? If anybody has the time.....
    what's it exactly that's troubling you? winning percentages vs rating? they're not relative to each other, but instead win % is inversely related to the opponent's rating. the higher the winning percentage, the lower rated opponents the player has been playing.

    a player with 50% score has been playing his peers. a player with 75% score has been playing people 200 points lower than himself. a player with 25% score has been playing people 200pts higher than himself etc. the player's rating ONLY improves/decreases if performs better/worse than the break-even performance level described above.
  7. 14 Oct '10 01:32
    Originally posted by Indonesia Phil
    Can anybody explain [in simple terms] the rating system...?? One of my current opponents has: played 76, won 36, lost 30, drawn 10, won 47% and is rated 1667.
    I have: played 59, won 41, lost 12, drawn 6, won 69% and am rated 1612.

    I am not a ratings maniac and should probably just stick to playing chess, but it doesn't seem to make any sense?? If anybody has the time.....
    Simple terms

    Beat someone lower rated your rating rises a little
    Beat someone higher rated your rating rises a lot

    Lose to someone higher rated your rating falls a little
    Lose to someone lower rated your rating falls a lot
  8. 14 Oct '10 02:14
    Got it, thanks to everyone!