Forum Archive : Ratings

Opponent's strength

From:   William Hill
Address:   illium@whills.demon.co.uk
Date:   8 April 1998
Subject:   yabs and yabe
Forum:   rec.games.backgammon
Google:   B151AE9F966826C752@whills.demon.co.uk

Hi Fibsters

There is something I don't quite understand here. yabs and yabe are both
bots (the same program as far as I know), the only difference being that
yabe plays players over 1700 while yabs plays players under 1700. The
latest ratings listing show yabs with a rating of 1948 and the last time I
played yabe it's rating was about 1780, exp for both in the 12500+ range.
Why the big difference? You might conclude that playing lower ranked
players could boost your rating by over 150 points! I'm currently 17-17
with yabe, so I think reasonable to say I'm close to it's standard. However
if I now assume yabs tactics could I expect my rating to climb much higher?

Surely this casts doubts on all bot type programs ratings, whereas humans
soon get tired of playing players well below their own standard on a
regular basis, bots will never grow tired of playing anyone. Even an
unselective bot would presumabley play about 90% of it's matches against
players below 1750 as only 10% of players or less are ranked above this.

Further, I view 1-pointers as a distinctly different type of game compared
to matches of 5 points and over where the cube is the dominant factor.
Comparing multi-point match players with 1-pointer is like comparing apples
with oranges as far as ratings are concerned.

I feel, having spent about 2 years on FIBS now, that most people
frustration with the dice in general stems from the fact that the ratings
system is inherently unbalanced. Perhaps it would be better to move to a
league type system, where for example a group of 16 player could play
against each other on a regular basis( weekends?). At least that way
players could make reasonable comparisons between themselves and others.

Regards William, illium on FIBS.

Tom Keith  writes:

Douglas Zare and Adam Stocks comment on this posting in their article
"Ratings: A Mathematical Study"
Did you find the information in this article useful?          

Do you have any comments you'd like to add?     



Constructing a ratings system  (Matti Rinta-Nikkola, Dec 1998) 
Converting to points-per-game  (David Montgomery, Aug 1998)  [Recommended reading]
Cube error rates  (Joe Russell+, July 2009)  [Long message]
Different length matches  (Jim Williams+, Oct 1998) 
Different length matches  (Tom Keith, May 1998)  [Recommended reading]
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)  [GammOnLine forum]
Fastest way to improve your rating  (Backgammon Man+, May 2004) 
Field size and ratings spread  (Daniel Murphy+, June 2000)  [Long message]
Improving the rating system  (Matti Rinta-Nikkola, Nov 2000)  [Long message]
KG rating list  (Daniel Murphy, Feb 2006)  [GammOnLine forum]
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)  [GammOnLine forum]
Ratings and rankings  (Chuck Bower, Dec 1997)  [Long message]
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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