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**Kenneth Sloan**

wrote:

Opinion:

Ratings are efficient only within the pool of players you are rated
against. It makes perfect sense that a player who has played no rating
games goes as unrated. You cannot assign an arbitrary value (0, 500,
100, whatever) to a player who has not played any games against the
rating pool, as this would skew the ratings eventually.

Not if you do it right!

And...in some (rare) cases, it turns out to be essential to make
*some* estimate of the rating to use for an UNR player. Once you
find this necessary, it's no longer a question of IF you can
assign a rating, but instead HOW MUCH CONFIDENCE you have
in that assigned rating.

I hope you'll agree that a rating of 1500, with a variance of 10^10, is
a reasonably accurate rating (for ALL players!). Not very precise - but
reasonably accurate.

I don't pretend to know the math involved, but this seems painfully
obvious to me. This is why you can play 1000 games on 5 different
servers and get 5 different ratings, probably not all that close to
each other. Also, a player can effectively and consistently play
opponents rated below himself and increase (INFLATE) his rating
slowly. You run into that scenario all the time on ICC and Playchess.

In a well designed rating system, you will NOT inflate your rating by
consistently playing low rated players.

In fact, we often hear the opposite complaint - that high rated players
see their ratings DEflate when forced to play low-rated competition.

when you hear both complaints, you are reasonably assured that the world
is nicely balanced.

Interesting thread, however.

http://chess-training.blogspot.com

--
Kenneth Sloan
Computer and Information Sciences +1-205-932-2213
University of Alabama at Birmingham FAX +1-205-934-5473
Birmingham, AL 35294-1170 http://www.cis.uab.edu/sloan/