View Full Version : Rating Differentials

Garvinator

27-06-2006, 04:52 PM

Does anyone know of a site that states how much one person should score against another over a series of games- ie players with 300 point difference play a 10 game match, what should the overall score be based just on rating.

I am sure there has to be a site somewhere and I admit I havent searched for one :oops:

Bill Gletsos

27-06-2006, 04:58 PM

Does anyone know of a site that states how much one person should score against another over a series of games- ie players with 300 point difference play a 10 game match, what should the overall score be based just on rating.

I am sure there has to be a site somewhere and I admit I havent searched for one :oops:Check the FIDE site at http://www.fide.com/official/handbook.asp?level=B0210

That shows the expected % based on the normal curve.

You can however use the superior logistic curve formula which Elo recommended in his book and is used by the USCF, Glicko and others:

P = 1/(1 + 10 ^ [D/400]) where D = the rating difference.

Garvinator

27-06-2006, 05:24 PM

Check the FIDE site at http://www.fide.com/official/handbook.asp?level=B0210

That shows the expected % based on the normal curve.

You can however use the superior logistic curve formula which Elo recommended in his book and is used by the USCF, Glicko and others:

P = 1/(1 + 10 ^ [D/400]) where D = the rating difference.

Thank you Bill, the reason I asked was that I wanted to see if AO was willing to state how many points start he could give an opponent. Since he thinks of himself as a GM, it should be plenty :P

I just wanted to see if his thoughts would match reality :uhoh: :wall:

qpawn

27-06-2006, 06:38 PM

Won't that site give only the ELO results?

Don't we use a funny glick thingy now?

Kevin Bonham

27-06-2006, 06:39 PM

Won't that site give only the ELO results?

Don't we use a funny glick thingy now?

The scaling of Glicko and ELO is the same so the same differentials should apply.

Bill Gletsos

27-06-2006, 07:10 PM

Won't that site give only the ELO results?I pointed out the FIDE site uses the normal distribution.

The USCF, Glicko amongst others use the logistic function.

Don't we use a funny glick thingy now?Garvin was interested in expected percentage. The difference between normal and logistic is minimal up to around a difference of 350 points, however even at 600 points there is only a 1.4% difference in expected percentage.

Igor_Goldenberg

28-06-2006, 10:06 AM

It would be an intresting experiment to see how accurate ELO formula in estimating the result. E.g a regression of result on three variables (ELO prediction for the game, colour and smallest rating in the pair) will show whether:

1. Whether ELO formula is a good estimator

2. How is it affected by the colour.

3. How is it affected by the level of players.

I strongly suspect that results will be different for high and lower rated players.

ACF rating officer must have a vast database of results.

Bill, do you want to do this exercise? Or to send data to me so I can run some statistical analysis?

Glenno

12-06-2007, 06:05 PM

It would be an intresting experiment to see how accurate ELO formula in estimating the result. E.g a regression of result on three variables (ELO prediction for the game, colour and smallest rating in the pair) will show whether:

1. Whether ELO formula is a good estimator

2. How is it affected by the colour.

3. How is it affected by the level of players.

I strongly suspect that results will be different for high and lower rated players.

ACF rating officer must have a vast database of results.

Bill, do you want to do this exercise? Or to send data to me so I can run some statistical analysis?

The website http://www.chesscenter.com/twic/event/sonas/sonasrat.html includes a graph that displays White's percentage score in relation to the difference in the ratings.

It would be an intresting experiment to see how accurate ELO formula in estimating the result. E.g a regression of result on three variables (ELO prediction for the game, colour and smallest rating in the pair) will show whether:

1. Whether ELO formula is a good estimator

2. How is it affected by the colour.

3. How is it affected by the level of players.

I strongly suspect that results will be different for high and lower rated players.

ACF rating officer must have a vast database of results.

Bill, do you want to do this exercise? Or to send data to me so I can run some statistical analysis?

I believe Bill did exactly this sort of modelling when Glicko was originally introduced, and concluded that Glicko is a far better predictor than ELO.

Igor_Goldenberg

19-06-2007, 09:23 AM

I believe Bill did exactly this sort of modelling when Glicko was originally introduced, and concluded that Glicko is a far better predictor than ELO.

As far as I understand, Glicko uses the same formula for expected result P=1/(1+pow10((D1-D2)/400)). That the one I'd like to test.

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