Estimating White's Advantage

General discussions about grading.
IanCalvert
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Estimating White's Advantage

Post by IanCalvert » Sat Aug 15, 2015 8:51 pm

In practice,White doubtless gets a higher % score than Black.

Does anyone know of reliable analysis of the variation in this facet of ECF (or even FIDE) stats?

Given the approximate linear relationship between rating difference and expected score implicit in the ECF system, I guess such information translated into rating points might well inform club level discussion.

Roger de Coverly
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Re: Estimating White's Advantage

Post by Roger de Coverly » Sat Aug 15, 2015 9:29 pm

IanCalvert wrote: Does anyone know of reliable analysis of the variation in this facet of ECF (or even FIDE) stats?
The best place to look is in a monstrous database that has a tree constructed.

As a for example I have one that gives

1. e4 (51.4% of all games) scores 53%
1. d4 ( 31.7%) scores 55%
1. Nf3 ( 7.7%) scores 55%
1. c4 ( 6.7%) scores 54%
1. g3 ( 0.7%) scores 54%
1. f4 (0.7%) scores 48%

Assuming the remaining 1.1% is 50%, that gives a weighted average of 53%

I'm not sure that's desperately important for modifying rating formulae. Back in the 1990s, the PCA rating list reflected colours.

What would worry me more would be the effect of treating stalemate as a win, as advocated by some. Apart from overturning much King and pawn endgame theory and with it the theory of many other worse but drawn endings, what would it do to white's winning percentage?

(edit) my rule of thumb is that having white is worth up to 5 ECF points. So if White is 165 and Black 170, they will score their grade if White wins 10 game match by 5.5 to 4.5, 55% in other words. (/edit)
Last edited by Roger de Coverly on Sat Aug 15, 2015 9:34 pm, edited 1 time in total.

NickFaulks
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Re: Estimating White's Advantage

Post by NickFaulks » Sat Aug 15, 2015 9:32 pm

FIDE has details of all individual rated games, including colour, since 2007. I expect I can get this.

edit: Having read Roger's post above, is his figure of 53%, which looks entirely credible, in fact all that is needed?

Brian Towers
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Re: Estimating White's Advantage

Post by Brian Towers » Sun Aug 16, 2015 9:58 am

Roger de Coverly wrote:What would worry me more would be the effect of treating stalemate as a win, as advocated by some. Apart from overturning much King and pawn endgame theory and with it the theory of many other worse but drawn endings, what would it do to white's winning percentage?
Surely following the example of hexagonal chess and awarding the player delivering stalemate 0.75 and the player on the receiving end 0.25 would be more sensible?
Ah, but I was so much older then. I'm younger than that now.

IanCalvert
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Re: Estimating White's Advantage

Post by IanCalvert » Sun Aug 16, 2015 10:22 am

NickFaulks wrote:FIDE has details of all individual rated games, including colour, since 2007. I expect I can get this.

edit: Having read Roger's post above, is his figure of 53%, which looks entirely credible, in fact all that is needed?
Roger and Nick, thanks very much.

As Nick might have guessed this is also part of my Cunning Plan to produce optimal team player strategies, for team discussion before a move is made. The individual Board strategies are essentially about " going for the win " or "playing safe" to maximise the probability that the team will win, given expected scores. in the statistical sense , on each Board. Unfortunately the objective function is non-linear but at least polynomial.

MartinCarpenter
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Re: Estimating White's Advantage

Post by MartinCarpenter » Sun Aug 16, 2015 11:02 am

Pointless anyway I'd think because the expected score for given players vary a huge amount :)

Firstly in general about how often they'll lose/draw/win (some people draw lots, some are very much more random). Also that white 'advantage' is a population average. Some players have a much larger one than in general, some less, the odd rare player even scores better with black.

Also major variance in terms of who people are playing - some are very good at stonewalling mildly stronger players, some super efficient vs weaker ones etc.

E Michael White
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Re: Estimating White's Advantage

Post by E Michael White » Sun Aug 16, 2015 11:24 am

Roger de Coverly wrote:The best place to look is in a monstrous database that has a tree constructed.

As a for example I have one that gives

1. e4 (51.4% of all games) scores 53%
1. d4 ( 31.7%) scores 55%
1. Nf3 ( 7.7%) scores 55%
1. c4 ( 6.7%) scores 54%
1. g3 ( 0.7%) scores 54%
1. f4 (0.7%) scores 48%

Assuming the remaining 1.1% is 50%, that gives a weighted average of 53%
Don't arbiter pairing methods and stratification of players into open/major/minor ensure stronger players get slightly more whites than blacks ?

Kevin Thurlow
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Re: Estimating White's Advantage

Post by Kevin Thurlow » Sun Aug 16, 2015 11:32 am

1.b3 happens about 0.4 % of the time and scores about 50 %.

I did a survey of Civil Service League games many years ago. Division 3 had (I think) 8 players and Division 4 had 6, so if you got promoted, you not only got tougher games anyway, you had to find two extra players, so we proposed having a 7-board division. One person at the AGM screamed that this was unfair as if you got fewer whites than the opposition, you were going to lose.

So the next year, I found that in Division 1, white scored 55 %, in Division 3, white scored 50 %, and in Division 5, white scored 45 %, so overall, it's about 50 %. I speculated that in Division 5, white had the disadvantage that he moved first and was very slightly more likely to make a catastrophic blunder first.

This doesn't help predict individual scores of course (as Martin said).

E Michael White
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Re: Estimating White's Advantage

Post by E Michael White » Sun Aug 16, 2015 11:51 am

Kevin Thurlow wrote:I speculated that in Division 5, white had the disadvantage that he moved first and was very slightly more likely to make a catastrophic blunder first.
Good points Kevin. Similarly white is more likely to lose on time, fall foul of the touch move rule or make an illegal move !

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David Shepherd
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Re: Estimating White's Advantage

Post by David Shepherd » Sun Aug 16, 2015 12:13 pm

I think a more meaningful comparison is the wins by white compared to the wins by black - there are a number of circumstances where both players are happy with a draw which I believe distorts the level of advantage when just looking at white overall percentages, as it smooths the statistic pulling it towards 50%.

Ian Thompson
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Re: Estimating White's Advantage

Post by Ian Thompson » Sun Aug 16, 2015 1:07 pm

E Michael White wrote:Don't arbiter pairing methods and stratification of players into open/major/minor ensure stronger players get slightly more whites than blacks ?
Why? I can see that pairing methods mean that stronger players are more likely to retain colour sequence than weaker ones, but not why they are more likely to get white than black.

Nick Grey
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Re: Estimating White's Advantage

Post by Nick Grey » Sun Aug 16, 2015 5:46 pm

Marginal at our levels.
As for team play most players play the same way (not really looking at match situation).
Opening 1.b3 against a player that is far to aggressive with any colour may well be best (you know me so well).
Personally I'll play something a bit more aggressive with white.

E Michael White
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Re: Estimating White's Advantage

Post by E Michael White » Mon Aug 17, 2015 9:41 am

Ian Thompson wrote:
E Michael White wrote:Don't arbiter pairing methods and stratification of players into open/major/minor ensure stronger players get slightly more whites than blacks ?
Why? I can see that pairing methods mean that stronger players are more likely to retain colour sequence than weaker ones, but not why they are more likely to get white than black.
Hello Ian,
My line of thinking was that under CAA pairings where a tournament has an odd number of boards, say 21 then the stronger player out of the two on each board in the first round is more likely to be white. In the case of 21 boards, 11 of the players will be white and likely stronger than their opps whereas only 10 black players could be stronger. Maintaining colour sequences over an odd number of rounds will likely but not necessarily give an overall rating advantage to white. This effect will reduce the apparent advantage that a straight % score shows to favour white.

Having 3 separate sections Open/Major and Minor is likely to increase the effect compared to having one large section. Also in the Open and Minor sections the distribution of ratings is likely to be skewed to the right and left respectively which may increase the effect. In League matches including 4NCL the effect may be reduced to around 0.

Roger de Coverly
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Re: Estimating White's Advantage

Post by Roger de Coverly » Mon Aug 17, 2015 9:55 am

E Michael White wrote: In the case of 21 boards, 11 of the players will be white and likely stronger than their opps whereas only 10 black players could be stronger.
Isn't that assuming you always give White to the top seed? I thought CAA rules required this either to be pre-determined by the calendar year as in the British Championships, or randomly assigned?

In any event, checking the percentages of results of five million recorded games from the whole of chess history isn't going to be affected by CAA rules.

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IM Jack Rudd
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Re: Estimating White's Advantage

Post by IM Jack Rudd » Mon Aug 17, 2015 9:56 am

E Michael White wrote:My line of thinking was that under CAA pairings where a tournament has an odd number of boards, say 21 then the stronger player out of the two on each board in the first round is more likely to be white. In the case of 21 boards, 11 of the players will be white and likely stronger than their opps whereas only 10 black players could be stronger.
The official rules for CAA pairings state that the top seed's round 1 colour is chosen randomly, which rather demolishes that argument.

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