Forum Archive :
Ratings
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




Ratings
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 Converting to pointspergame (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 RintaNikkola, 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 onepoint matches? (David Montgomery, Sept 1995)
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