Re: Hastings

Chess One wrote:
"Andy Walker" <anw@xxxxxxxxx> wrote in message news:flhf1p$haq$1$8300dec7@xxxxxxxxxxxxxxxxxxx
In article <jOudndzzY_dNtOHanZ2dnUVZ_jednZ2d@xxxxxxxxxxx>,
Chess One <OneChess@xxxxxxxxxxx> wrote:
ECF have agreed to be interviewed by Chessville - would you like to compose
a question based on what follows, that I can present to them in your name?
Not really. ECF are "onside" on this, more-or-less; see
"http://www.bcf.org.uk/grading/2006/stat-gs_oct06.htm";. There is
some later info floating around, but I haven't seen it on the Web.

Thank you for this resource; I see that the 2 initial statements were

"David Welch came up with the hypothesis that the oddities in the conversion from FIDE to ECF were due to anomalies in the ECF grading system. Subsequently analysis by Dave Thomas showed that:
1) The actual performance of players did not appear to correspond to the theoretical performance. This means that whereas for a grading difference of 25 points the stronger player should score 75%, his actual score is more like 68%.

This is a well known effect. It is inherent in any system where the expected score is a non-linear function of rating difference. An alternate explanation can be made using the fact that published ratings are not precise - they are a mixture of knowledge (previous games) and ignorance (everything else).

It's not a problem. This has been explained to you several times, Mr Innes - are you having a senior moment?

FIDE has the same "problem". So does USCF. If you have a problem matching ECF with FIDE, I think you need to look further for the cause - this is not it.

I suspect that "anomalies" are due to edge effects and game conditions. A 2400 player has different goals and behavior when he is at the top of the local pool than he does when he is at the bottom of the international pool. Second: Elo systems largely ignore the draw percentage. Some game conditions *encourage* draws (e.g., round robins) while others encourage decisive results (e.g., big money Swiss events). A 2400 playing in the World Open is playing a different game that the sams 2400 who has somehow been invited to a 10-player round robin.
At the lowest end of the FIDE scale, their used to be (I think it's fading now) an effect related to the FIDE rule that below-standard results are not rated by FIDE (for new players). Most players who have just gotten their first FIDE rating can be expected to LOWER that rating over the next several events.


...
In the US the cause of rating inflation is clear in 2 respects;- here there are 'awards' which fix ratings so that on attaining 2200, eg, that becomes a permanent 'rating-floor' for that player, despite the fact that 3 years later actual performance has slipped to 1950 on the same scale, the result of games is still scored against the 2200 number.

This seems to make a monkey out of Elo's idea by deliberately removing ratings from any mathematical basis whatever!

Secondly, popularity of tournament chess can place players within the same approximate rating range, consistently either at the top or the bottom of it: A friend has played in half a dozen money tournaments now where he is in the top 10% of players in a [eg] 1500-1900 class, and he often wins money thereby, but on the broader scene he must play higher rated players than his nominal 1850 rating, and so loses the points he gained against the lower rated ones - and he is quite happy about this because then he can keep winning money for his wins!

This analysis is specious. As noted above, your performance when playing against lower rated players tends to be LESS than predicted, and hence you tend to lose points (not gain them, as you say). By the same token, when you play higher rated players, it is likely that you will GAIN rating points.

In any event, none of this is inflationary.

Floors are, indeed, evil. However, with careful measurement and tweaking of parameters it is possible to make a rating system inflate, deflate, or remain stable, depending on what your want to do. In USCF ratings, we use the "bonus point threshold" as a design handle to control inflation/deflation. It's been working remarkable well for the past 5 years or so.



--
Kenneth Sloan KennethRSloan@xxxxxxxxx
Computer and Information Sciences +1-205-932-2213
University of Alabama at Birmingham FAX +1-205-934-5473
Birmingham, AL 35294-1170 http://KennethRSloan.com/
.

Relevant Pages

  • Re: New Rating System Proposal
    ... >>consistently compete against 7 other players should deserve a rating ... which awards any form of ranking to people who don't play. ... Games have winners and losers. ...
    (rec.games.trading-cards.jyhad)
  • Re: New Rating System Proposal
    ... one reason why it's irrelevant to talk about what players in the boondocks ... could be doing if they wanted rating points badly enough. ... It may be reasonable to suspect that a player who doesn't regularly play ... >> what one person has to go through to make tournaments happen for themselves ...
    (rec.games.trading-cards.jyhad)
  • Re: Rating: USCF and/or FIDE?
    ... January 2006 list with a rating of 1993, ... FIDE still appears to consider me as unrated. ... I hope that I still have the 2.5/7, so that my next 0.5/3 3 will put me on the list - but if not, I'll just have to work harder (or wait as lower and lower rated players show up at the US Open - I played a 1900FIDE player this year, and expect to see more as time goes by). ...
    (rec.games.chess.misc)
  • Re: Hastings
    ... The actual performance of players did not appear to correspond to the ... expected score is a non-linear function of rating difference. ... matching ECF with FIDE, I think you need to look further for the cause - ... In the US the cause of rating inflation is clear in 2 respects;- here ...
    (rec.games.chess.misc)
  • Re: McMakko (was: Ranking system in European countries)
    ... McMakko suffers from the same flaws as the EGF rating system: ... > - Handicap games are included. ... > unfair because different players have different probability functions, ...
    (rec.games.go)