09 Jul '03 17:38>
This thread highlights some problems with the current rating system which I am about to address.
http://www.redhotpawn.com/board/showthread.php?id=575
The key point is that new joiners to the site need some time to 'find their level'. Also, established members currently have good reason to avoid playing new members because it may reflect inaccurately on their own rating should the new joiner be of a high-standard.
For this reason I intend to change the system so that players with fewer than 20 completed games will be assigned a 'provisional' rating, and so that established players are not put-off playing new joiners.
Here is what I intend. It closely resembles other chess rating systems so should be familiar to many players already. Note that the main calculation is unchanged - all that differs is the way that new players affect the ratings.
1) For the first 20 games you play on RHP, your rating is calculated as an average of all your results. Each result is scored by adding 400 to your opponent's rating if you win, subtracting 400 from your opponent's rating if you lose, and copying your oponnent's rating if you draw. The exception to this is if your opponent has also played fewer than 20 games, in which case subsitute the value 200 for the 400s above.
2) If your opponent has played fewer than 5 games, then their rating will be treated as 1200 for the sake of the calculating your rating, even though their current provisional rating may not actually be 1200.
3) Once you have played 20 games, the rating is calculated using the
formula...
CR + (K * (S - WE)) * PA
Where...
CR = Your Current Rating
K = 32, unless your rating > 2100, then K = 24, unless your rating > 2400, then K = 16
S = Score (Win=1, Draw=0.5, Loss = -1)
WE = Win Expectancy. This is calcualted as 1 / (10^(RD/400) + 1) where RD is the difference (positive) between yours and your opponent's rating.
PA = Provisional Adjustment. If you opponent has played fewer than 20 games, then PA = 0.5, otherwise PA = 1
All thoughts welcome...
http://www.redhotpawn.com/board/showthread.php?id=575
The key point is that new joiners to the site need some time to 'find their level'. Also, established members currently have good reason to avoid playing new members because it may reflect inaccurately on their own rating should the new joiner be of a high-standard.
For this reason I intend to change the system so that players with fewer than 20 completed games will be assigned a 'provisional' rating, and so that established players are not put-off playing new joiners.
Here is what I intend. It closely resembles other chess rating systems so should be familiar to many players already. Note that the main calculation is unchanged - all that differs is the way that new players affect the ratings.
1) For the first 20 games you play on RHP, your rating is calculated as an average of all your results. Each result is scored by adding 400 to your opponent's rating if you win, subtracting 400 from your opponent's rating if you lose, and copying your oponnent's rating if you draw. The exception to this is if your opponent has also played fewer than 20 games, in which case subsitute the value 200 for the 400s above.
2) If your opponent has played fewer than 5 games, then their rating will be treated as 1200 for the sake of the calculating your rating, even though their current provisional rating may not actually be 1200.
3) Once you have played 20 games, the rating is calculated using the
formula...
CR + (K * (S - WE)) * PA
Where...
CR = Your Current Rating
K = 32, unless your rating > 2100, then K = 24, unless your rating > 2400, then K = 16
S = Score (Win=1, Draw=0.5, Loss = -1)
WE = Win Expectancy. This is calcualted as 1 / (10^(RD/400) + 1) where RD is the difference (positive) between yours and your opponent's rating.
PA = Provisional Adjustment. If you opponent has played fewer than 20 games, then PA = 0.5, otherwise PA = 1
All thoughts welcome...