i'm expecting that my rating will go up not down. i don't know y. Game 1450982 Game 1469739 1499125
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.
Originally posted by BowmannThat's the standard approach for ELO provisional ratings.
Ridiculous.
Consider the unrated player whose first event is strong:
Event 1--
opponent's rating/result
2401 / loss
2323 / loss
2296 / loss
2189 / loss
2250 / loss
This player gains an initial provisional rating of 1892.
Then she enters another event with a broader range of players.
Event 2--
1568 / loss
1205 / win
1419 / draw
1679 / loss
1306 / win
Despite an even score, the rating should drop more than 200 points to 1663. This rating reflects only the simplest calculation of +/- 400. If performance rating is factored in, the player's performance of 1435 in the second event could take her rating down further.
Provisional ratings are inexact and unreliable. Those who understand the system have been known to abuse it from time to time. At another site I've played at, there are a few inactive players with terribly high ratings who have no wins--a consequence of abuse.
Originally posted by amir1My rating went down from 1467 to 1445 after I won my third game here: Game 824429
I've read the FAQ and your detailed posts.😕
But still I can't figure it out - can some1 give me a specific example where player-1 wins and his rating drops?!
don't be afraid to bombard me with technical calculations if needed...
Thanks.