Is there any adjustment for colour in the rating system?

General discussions about ratings.
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Mark Hannon
Posts: 55
Joined: Fri Jul 30, 2010 9:53 am

Is there any adjustment for colour in the rating system?

Post by Mark Hannon » Tue Nov 19, 2013 12:13 pm

Are the ECF grades (or any other system) adjusted in any way to allow for black or white games?

Roger de Coverly
Posts: 21291
Joined: Tue Apr 15, 2008 2:51 pm

Re: Is there any adjustment for colour in the rating system?

Post by Roger de Coverly » Tue Nov 19, 2013 12:20 pm

Mark Hannon wrote:Are the ECF grades (or any other system) adjusted in any way to allow for black or white games?
I think the relatively short-lived PCA ratings from 1993 onwards did this, I'm not aware of any national rating systems that currently have this refinement. Provided you have colour data for each individual game, you would just subtract something to the Black expected score and add the same from White's. The net effect would be that in a draw between players of equal rating, the player of White would lose a fraction and the player of Black gain a fraction.

If you used 52-48, then the expected score for Black is 0.48 which means a gain of 0.02 for a draw. So 0.2 of a rating point per game for K=10. At the 400 point extremities, ignoring colours might be necessary, implying a tapering of the formula.

In practice, the extension of the International rating system into areas where players can expect to make rapid improvements has reduced its reliability as a means of ranking players. In this season's 4NCL, teams are allowed to elect to use the ECF national grades to place their squad in ranking order. A number appear to have done this.

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