Fide on Chess Ratings: Summary Report of QC Council

Alexandra Kosteniuk's Chess Blog for Daily Chess News and Trivia (c) 2013

Hi everyone,

SUMMARY REPORT OF QC COUNCIL MEETING IN ATHENS
1-2 June 2013 Annex QC1 

ANALYSIS

 

QC consultant Jeff Sonas has developed a "Retroactive Rating Calculator" so that FIDE can investigate hypothetical changes to the rating regulations. This allows us to determine what would have happened to all ratings calculated since 2008 if those hypothetical regulations had already been in effect, starting in 2008. This essentially provides a "beta-test" on proposed changes, to ensure the intended positive consequences would actually have occurred, and to identify any unintended negative consequences resulting from the changes. 

The QC has used this "RRC" to investigate a number of possible changes to rating regulations, considering their impact on three main areas:
- absolute magnitude of ratings (i.e. inflation/deflation)
- the total number of rated players
- correlation between ratings and future results (i.e. predictive ability of ratings), both for the entire pool and for targeted sub-groups.

(1) K-Factors
There seems no justification for modifying the K=10 coefficient currently used, as increasing this coefficient would push top players' ratings even higher than they currently are, and would reduce the accuracy of top ratings. However, increasing the other two K factors by 33% (K=15 becomes 20, K=30 becomes 40) will increase the accuracy of ratings throughout the entire rating pool without substantially increasing absolute magnitude of ratings. A smaller increase of 20% (K=15 becoming 18, K=30 becoming 36) would improve accuracy even slightly more, but the 20/40 coefficients were preferred in order to preserve the simplicity of manual rating change calculations.

(2) Sean Hewitt Proposal (maintaining most dynamic K-factor for playersSean Hewitt of the English Chess Federation suggested this simple modification, which would allow freer rating change for young developing players, especially those who play frequently at a young age and thereby hit 30 games early in their development. Recent changes to the rating regulations (including the move to a monthly list, as well as a larger population of low rated opponents so that players surpass 30 rated games sooner) make this rule change very appealing, and it has a very significant positive impact on the accuracy of ratings for all players, even for players out to 100+ games played. 

(3) For unrated players, only 5 games required for first rating, and all events and all games vs rated opponents count toward first rating, starting with first event where player scores >0% against rated opponents. 

This recommendation comes from the retroactive analysis of rating accuracy since 2008, and is a major change in the philosophy of the rating system. Prof. Elo’s principles maintained a system that blocks new players from achieving a first rating in many different ways. Jeff Sonas showed us that it is much better to provide a first rating more easily, and then allow players to regulate their rating by playing chess.

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