Ratings

Forum Archive : Ratings

 Experience required for accurate rating

 From: Jon Brown Address: jonbrown@hotmail.com Date: 14 November 2002 Subject: statistics Forum: rec.games.backgammon Google: NHNA9.117888\$c51.35150418@twister.nyroc.rr.com

I have a few questions related to sample size in statistics:

1. About how many experience points are necessary to get an accurate
measure of your rating ((how does the answer change if you are only playing
the same computer opponent, with a fixed rating  who performs at the same
level (ex. playing offline against snowie) as opposed to playing opponents
of varying levels and ratings (ex. playing on gamesgrid)).

A related question:

2. About how many matches are needed to determine with a reasonable level
of statistical certainty the stronger of two players who are only playing
each other in 1pt or only 7pt. or only 25 pt matches?

 Peter Schneider  writes: Well... what do you mean with accurate? I'd guess that I'm more than 50% of the time more than 20 rating points away from the rating which corresponds to my average skill. (Yes, also upwards! ;-) ) The interval spanned within the last months was 1740-1860. Kit Woolsey is told to have been seen below 1800 on FIBS once. So I think for me, after having played many thousand games, I have a 95% probability to be within a range of 1760-1820. The center of the oscillations gives a better number, but it takes so many games to determine, that I hopefully have improved inbetween. (But true, this could be detected by sophisticated statistical methods.) I'd say that a rating snapshot at best gives an indication of the playing class (like intermediate or advanced), with a significant probability to be off by 1 class. Last not least, imho the online rating does not say much about the play over the board.

### 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)