Forum Archive : Ratings

Table of win rates From:   William C. Bitting Address:   wbitting@crl.com Date:   16 August 1995 Subject:   Re: Strength of program Forum:   rec.games.backgammon Google:   40th53$er7@crl9.crl.com Clearly the EXPERIENCE NUMBER is key to judging the validity of a rating number. While all FIBS players start at 1500, because of a multipler to the rating changes, which starts at 5(!) and declines to 4 at an experience of 100; 3 at 200, etc., 1500 is not what many FIBSsters will have as their rating when their experience is 200, not to mention 2000. Some players decline to near 1300, and lower, quickly. Others like 'loner', 'mloner, 'STLguy', etc., quickly pass 1700 or 1800, not to mention 1900 and 2000 by the former two! So, while it is true that a 1700 or 1800 rated player may win 8 of 10 seven point matches against many new FIBS players, that won't be true when the 1500 rated, 0 experience, player is one of the loner's, etc.. Nor will it be true when the 1500 rated player has a couple of thousand experience points unless, of course, the player 1700 to 1800 player is somebody on the way to 1900 or 2000. The following table is the "batting average" the favorite must achieve to maintain his rating at various rating differences. For players whose experience level is over 2000, it may have considerably more validity than for players whose experiece level is under 400. Players with experience levels under 500 and ratings of mid 1700, not to mention over 1800, may be still be underrated simply because of not having played enough matches! BATTING AVERAGE FOR FAVORITE TO MAINTAIN HIS RATING. (For the underdog, his average is 1 minus the favorite's.) rate points in match diff 1 3 5 7 9 11 --------------------------------------- 0 .500 .500 .500 .500 .500 .500 100 .529 .550 .564 .576 .585 .594 200 .557 .598 .626 .648 .666 .682 300 .585 .645 .684 .714 .738 .759 400 .613 .689 .737 .772 .799 .822 500 .640 .730 .784 .821 .849 .871 600 .666 .768 .824 .861 .888 .908 700 .691 .802 .858 .894 .918 .935 If the proposition is that a player is going to win 8 of 10 seven point matches against EXPERIENCED 1500 rated players, that batting average is .800. From the above table we might therefore concluded the rating of such an .800 hitter should be about 450 points over 1500, or 1950! Thus a player who correctly guages that his batting average is .800 against experienced 1500 rated players, may just as well judge that he is underrated until his rating reaches 1950 rather than that the 1500 player is overrated. If the propostion was winning 10 while loosing 2, then the batting average is .833, and the batter should be above 2000 on his rating index given enough experience! Good Dice! wcb on FIBS   Did you find the information in this article useful?           Do you have any comments you'd like to add?

 

Ratings

Constructing a ratings system  (Matti Rinta-Nikkola, Dec 1998) 

Converting to points-per-game  (David Montgomery, Aug 1998) 

Cube error rates  (Joe Russell+, July 2009) 

Different length matches  (Jim Williams+, Oct 1998) 

Different length matches  (Tom Keith, May 1998) 

ELO system  (seeker, Nov 1995) 

Effect of droppers on ratings  (Gary Wong+, Feb 1998) 

Emperical analysis  (Gary Wong, Oct 1998) 

Error rates  (David Levy, July 2009) 

Experience required for accurate rating  (Jon Brown+, Nov 2002) 

FIBS rating distribution  (Gary Wong, Nov 2000) 

FIBS rating formula  (Patti Beadles, Dec 2003) 

FIBS vs. GamesGrid ratings  (Raccoon+, Mar 2006) 

Fastest way to improve your rating  (Backgammon Man+, May 2004) 

Field size and ratings spread  (Daniel Murphy+, June 2000) 

Improving the rating system  (Matti Rinta-Nikkola, Nov 2000) 

KG rating list  (Daniel Murphy, Feb 2006) 

KG rating list  (Tapio Palmroth, Oct 2002) 

MSN Zone ratings flaw  (Hank Youngerman, May 2004) 

No limit to ratings  (David desJardins+, Dec 1998) 

On different sites  (Bob Newell+, Apr 2004) 

Opponent's strength  (William Hill+, Apr 1998) 

Possible adjustments  (Christopher Yep+, Oct 1998) 

Rating versus error rate  (Douglas Zare, July 2006) 

Ratings and rankings  (Chuck Bower, Dec 1997) 

Ratings and rankings  (Jim Wallace, Nov 1997) 

Ratings on Gamesgrid  (Gregg Cattanach, Dec 2001) 

Ratings variation  (Kevin Bastian+, Feb 1999) 

Ratings variation  (FLMaster39+, Aug 1997) 

Ratings variation  (Ed Rybak+, Sept 1994) 

Strange behavior with large rating difference  (Ron Karr, May 1996) 

Table of ratings changes  (Patti Beadles, Aug 1994) 

Table of win rates  (William C. Bitting, Aug 1995) 

Unbounded rating theorem  (David desJardins+, Dec 1998) 

What are rating points?  (Lou Poppler, Apr 1995) 

Why high ratings for one-point matches?  (David Montgomery, Sept 1995) 

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