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http://www.goratings.org/ now has historical ratings lists http://lifein19x19.com/viewtopic.php?f=13&t=12179 
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Author:  Rémi [ Fri Oct 30, 2015 3:05 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
hyperpape wrote: P.S. Surely there's a timing problem with citing your data. Both goratings and Dr. Bae Taeil's data show Iyama getting even stronger in the past year or two. But his international record reflects more than 5 years of play. That is true. Also note that 1221 is not very statistically significant in terms of proving inferiority. Assuming a uniform prior over the win rate, the posterior probability that a player with 21 wins is stronger than a player with 12 wins is only 94%. 
Author:  Rémi [ Mon Nov 09, 2015 3:36 am ]  
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis  
Today, Iyama reached #3. Almost 4 months without a loss, 20 victories in a row. Japan is too easy for him: http://www.goratings.org/players/601.html

Author:  Sennahoj [ Mon Nov 09, 2015 3:56 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Remi, have you checked how well calibrated the exante probabilities of this model is? That is, in games where the models predict around X% winning chance for black, how large fraction of those matches are actually won by black? 
Author:  Uberdude [ Mon Nov 09, 2015 4:09 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Sennahoj, I don't know about these pro games, but I recall WHR did better than KGS's rating system in predicting the win rates of KGS games when that was analyzed some time ago. 
Author:  Rémi [ Mon Nov 09, 2015 4:21 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Sennahoj wrote: Remi, have you checked how well calibrated the exante probabilities of this model is? That is, in games where the models predict around X% winning chance for black, how large fraction of those matches are actually won by black? The details of my method are described in the WHR paper: http://www.remicoulom.fr/WHR/WHR.pdf What I try to optimize is how frequently the winner of a game had the best rating before the game. 
Author:  Sennahoj [ Tue Nov 10, 2015 5:17 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
thanks, I understand. It would still be interesting to see if the exante winning probabilites are well calibrated (in that sense  that black wins about X% when the exante winning probability is X%). It is not obvious that this will be the case, even if the model is super good at "getting the sign right", i.e. predicting which player will win. Just to be clear, this is not a criticism of the methodology or anything like that I would be happy to do some analysis if you'd give me some data, pm me if you're interested. The reason this is interesting is that if the exante probabilities are sufficiently well calibrated, it is meaningful to look those numbers  otherwise it's not, and they should just be thought of as some "intermediate" quantities inside the model, which are used for calculating the final output. 
Author:  hyperpape [ Wed Nov 11, 2015 7:12 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Amusingly, the US's Andy Liu is currently rated 175ththe power of winning four straight games with your only loss being in 2011. He'll surely drop a little once the Kansai tournament is over (and you can't read much into Western players' ratings anyway, because of the lack of games and possibility of selective inclusion). 
Author:  handa711 [ Thu Nov 12, 2015 11:42 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
I am baffled by Lee Changho's domination. Noob question: where is Go Seigen? 
Author:  hyperpape [ Thu Nov 12, 2015 3:05 pm ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
It appears he's not in the database. There's spotty coverage for the earlier yearsI can find Kitani Minoru, but with only 17 games. As for Lee Changho, why are you baffled? His results were the best in the world by a substantial amount for a decade. 
Author:  handa711 [ Sat Nov 14, 2015 8:43 pm ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
hyperpape wrote: It appears he's not in the database. There's spotty coverage for the earlier yearsI can find Kitani Minoru, but with only 17 games. As for Lee Changho, why are you baffled? His results were the best in the world by a substantial amount for a decade. I'm baffled by the length of his dominance. Possibly because I wasn't even born back then. 
Author:  trout [ Sat Nov 14, 2015 9:13 pm ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Read the following article. You will see how dominant he was. http://senseis.xmp.net/?YiChangHo 
Author:  hyperpape [ Sun Nov 15, 2015 8:16 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
It is amazing. The only 20th century player I know to compare it to is Go Seigen[1]. One difference is that Lee Changho was eventually surpassed as he aged and Lee Sedol came into his prime. Would Sakata have been able to surpass Go in the 1960s if the latter's career hadn't been cut short by an accident? We'll never be able to do more than guess (but check out this interview: http://www.andromeda.com/people/ddyer/a ... unter.html). P.S. I found Go Seigen in the goratings page (http://www.goratings.org/players/856.html), but he only has five games from after his peak. [1] Another player you might ask about is Shusai, but there I have no idea. 
Author:  Jhyn [ Mon Nov 16, 2015 10:12 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
I see in your paper that you applied your algorithm to the KGS database. If you don't mind, I had a question about the evaluation of the results. In your article, you say that "WHR significantly outperforms the other algorithms". The previous table shows a prediction gain of 0.6% compared to a simple ELO system. It looks like a small gain to my untrained eye; nevertheless I understand that the prediction rate cannot increase too much over 50% (if a game is a true 50/50 coin flip, no algorithm can do better than 50%). As a consequence the prediction rate seems to be dependent of the database (many lopsided matchups, e.g. 90%/10%, would increase the prediction rate of all systems). Therefore it seems hard to me to get a good idea of how significant the prediction gain actually is. I thought about the following : if we took a large "fake" database with win ratios actually distributed as a gaussian centered on 0.5 and some wellchosen variance (corresponding to the apparent variance in the KGS database), what would be the prediction rate of the "perfect algorithm" (that predicts the correct win probability every time)? It seems to me this would be the best theoretically possible prediction rate. I hope my question makes sense. 
Author:  hyperpape [ Tue Nov 17, 2015 7:49 pm ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
I was intrigued by the discussion with macelee, so I grabbed Iyama's games against the current top twenty players. If I have not made any transcription errors, the correct list is below. His record is 1221. By year: 2002: 01 2005: 01 2006: 01 2007: 11 2008: 12 2009: 03 2010: 13 2011: 53 2012: 00! 2013: 01 2014: 12 2015: 23 You can see that he's doing a bit better as time goes on. Still, his international results from 20132015 are mediocre relative to his current rating. If you split the games into 20022010 and 20112015, you get records of 312 and 99 respectively, though there's no principled reason why you should include 2011 and not 2010 (which gives you 1012). 2010 is notable because it's the first year he plays someone rated lower than himself. I'd like to calculate how he's performing relative to the model's predictions, but I actually have to look up something to do that . Code: Date,W/L,Opponent,Iyama's Rating,Opponent's Rating
20021205,L,Chen Yaoye,3236,3313 20051108,L,Chen Yaoye,3289,3378 20060110,L,Gu Li,3296,3472 20071212,L,Chen Yaoye,3385,3403 20071212,W,Zhou Ruiyang,3385,3405 20080414,L,Lee Sedol,3392,3541 20080425,L,Kang Dongyun,3393,3457 20081118,W,Chen Yaoye,3398,3415 20090413,L,Kang Dongyun,3407,3451 20091130,L,Chen Yaoye,3414,3449 20091201,L,Kim Jiseok,3412,3417 20100607,L,Lian Xiao,3420,3378 20100725,L,Gu Li,3425,3451 20101019,L,Lee Sedol,3434,3538 20101125,W,Lee Sedol,3455,3516 20110516,W,Lee Sedol,3455,3516 20110518,W,Gu Li,3455,3459 20110810,W,Gu Li,3461,3463 20110811,W,Choi Cheolhan,3461,3478 20110813,L,Park Jungwhan,3461,3506 20110814,W,Jiang Weijie,3461,3426 20110817,L,Park Yeonghun,3461,3418 20110819,L,Jiang Weijie,3461,3426 20130630,W,Park Jungwhan,3479,3554 20131111,L,Chen Yaoye,3478,3492 20140328,L,Zhou Ruiyang,3478,3481 20140817,L,Lee Sedol,3482,3506 20141203,W,Park Jungwhan,3489,3571 20150105,W,Park Yeonghun,3493,3448 20150108,L,Chen Yaoye,3494,3480 20150303,W,Mi Yuting,3501,3476 20150304,L,Kim Jiseok,3501,3476 20150314,L,Ke Jie,3502,3581 
Author:  Rémi [ Wed Nov 18, 2015 3:35 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Jhyn wrote: I thought about the following : if we took a large "fake" database with win ratios actually distributed as a gaussian centered on 0.5 and some wellchosen variance (corresponding to the apparent variance in the KGS database), what would be the prediction rate of the "perfect algorithm" (that predicts the correct win probability every time)? It seems to me this would be the best theoretically possible prediction rate. I hope my question makes sense. Rating algorithms must be tested on real data. You can generate artificial data based on some model, and then the best rating system would be the rating system that assumes this model. But the fact that an algorithm is the best to predict the artificial data does not imply that it will be the best to predict the real data. The only way to measure the ability of an algorithm to predict real game outcomes is to measure how well it predicts real game outcomes. Rémi 
Author:  Jhyn [ Wed Nov 18, 2015 10:56 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Rémi wrote: Rating algorithms must be tested on real data. You can generate artificial data based on some model, and then the best rating system would be the rating system that assumes this model. But the fact that an algorithm is the best to predict the artificial data does not imply that it will be the best to predict the real data. The only way to measure the ability of an algorithm to predict real game outcomes is to measure how well it predicts real game outcomes. Thank you for your answer, but I think you misunderstood my point. The goal would not be to test the algorithm itself, it would be to get a rough idea of the theoretical best prediction rate that could be achieved ("rough" because it would be an approximation of the KGS database). Going from 55.7% to 55.8% of prediction rate would look very different if you can give a convincing argument the prediction rate should be capped at around, say, 57%, as compared as if you could (theoretically) reach 100%. 
Author:  MP4Life [ Sat Nov 21, 2015 4:25 pm ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
I can't see how a player that nearly never plays international games can be ranked #3 in the world. I like Iyama but he doesn't deserve that spot. All his competitors in Japan are out of top 20 in the world(most would actually think top 50) so how can his vicotories count so high? 
Author:  sparky314 [ Sat Nov 21, 2015 11:37 pm ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Continual victories against his domestic opponents will continue to increase his rank, even if marginal, unless there's a cap in the algorithm where one will no longer gain points unless he plays someone strong enough. I haven't read the paper for the WHR algorithm. He is on a hot streak. Unless I missed a game, still might hold all 7 big titles in Japan at the same time. But I would like to see Japan compete better at an international level. 
Author:  SaiLens [ Mon Nov 30, 2015 5:45 am ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
Jhyn wrote: Rémi wrote: Rating algorithms must be tested on real data. You can generate artificial data based on some model, and then the best rating system would be the rating system that assumes this model. But the fact that an algorithm is the best to predict the artificial data does not imply that it will be the best to predict the real data. The only way to measure the ability of an algorithm to predict real game outcomes is to measure how well it predicts real game outcomes. Thank you for your answer, but I think you misunderstood my point. The goal would not be to test the algorithm itself, it would be to get a rough idea of the theoretical best prediction rate that could be achieved ("rough" because it would be an approximation of the KGS database). Going from 55.7% to 55.8% of prediction rate would look very different if you can give a convincing argument the prediction rate should be capped at around, say, 57%, as compared as if you could (theoretically) reach 100%. Keep in mind that every prediction needs to be based on data. Every rating algorithm I know of only uses past records, as it's ostensibly the most efficient option. A more convoluted model (thus adding variance, allowing for better prediction in the first place) would have to take more data into account than pure W/L and rating difference. These additional parameters could be gamerelated (winning margin  a terrible idea, i know), individual characteristics (e.g.: average thinking time) for the relevant match characteristics (here: time setting) and so on and so forth. Of course you would first have to have those data available, then invest additional computing power,... but there's only so much you can squeeze out of a single binary variable. 
Author:  hyperpape [ Mon Jan 02, 2017 4:58 pm ] 
Post subject:  Re: http://www.goratings.org/ now has historical ratings lis 
DrStraw wrote: One fact I find remarkable: before 1988 all the top three were Japanese; since 1994 not a single Japanese player has been in the top 3. This is an amazingly quick turnaround. Also interesting is that in 36 years only 5 players have been at the top. Something has now changed, and Cho Hunhyeon first hits 1st place in 1984. I supposed some older games might have been added? Unfortunately, there still aren't any of his games against Japanese players from the early 80s. 
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