5 ms·

Chess rating system provides the best predictor of World Cup success

35 points by datageek 16y ago

CWuestefeld 16y ago
Table tennis uses a similar system. My wife used to play competitively, and people at the club would always ask each others' ratings when looking for a good match. Of course, a single number can only tell you so much -- it's a very gross generalization of skill. A lower-score player can have a particular strength corresponding to another's weakness, thus leading to a win for the (generally) weaker player. I imagine that this is similarly true for soccer teams.
- carbocation 16y ago
  Absolutely. What you're describing is basically an interaction effect. Looking at all the data, A may be better than B by virtue of the fact that A is better than X, Y, and Z, while B is worse than them. But A has a specific weakness (an unprotected heel) and B has a rarely useful strength (ability to shoot arrows into the heel) that leads to B defeating A.
- lotharbot 16y ago
  > "Of course, a single number can only tell you so much -- it's a very gross generalization of skill." In a system where new players can enter after competition has begun (and others have accumulated points), there's also a good chance that a new player will not yet have had enough time to accumulate a score that's in line with their actual skill, which can lead to some misleading matchups. Depending on the details of the ranking system and the ease of finding similarly-ranked partners, it can take a long time to converge to a "true" rating. For example: I had friends in college who played competitive card games that had some sort of lifetime ranking (Bridge, perhaps?) Because they were young, they were often the lowest seed in tournaments. Despite above-average skill, they were normally eliminated by the very most skilled teams in the first round, and therefore had few opportunities to accumulate points against more equal competition. Once they finally broke through and won a couple of tournaments, there was a bit of a snowball effect as they moved out of the lowest seed.
carbocation 16y ago
Sweet. I love Elo points a lot (so much so that they are how my startup ranks U.S. colleges: http://college.mychances.net/college-rankings.php http://college.mychances.net/college-rankings.php ). The author poses the following question: "[...] like the economy, are Elo ratings subject to bouts of inflation?" Since the amount of points available depends on the number of individuals participating, Elo points should indeed be subject to inflation.
- grasshoper 16y ago
  Cool site. I knew Harvard's yield was higher than the other schools, but I didn't expect Stanford and Yale to have higher yields so much higher than Princeton. I don't think this was true a few years ago when I was applying to schools. How are you gathering information about where students were accepted? And where is Caltech in all this? Also, you know that you can't just add the 25th/75th percentiles for individual SAT sections and come up with overall results, right?
  - carbocation 16y ago
    Thanks. Re: Caltech - if I recall correctly, there wasn't enough data for it to produce results when I ran the algorithm last year. I suspect we'll have enough this year (I'll probably re-run the algorithm in a few weeks). Basically the entire site is dedicated to gathering information from students, and then transforming that data into something useful for them. So I gather the info directly (over 250,000 college apps from 50,000 different people are in the system by now). I honestly have no idea why I thought I could get away with adding together the 25th and 75th percentiles for SAT subscores on that page; it's not something I do elsewhere on the site. (I'm using "I" here since I'm sure this is my fault alone.) Thanks for pointing that out! Edit: I forgot about Princeton. The Elo points can be a bit hard to decipher on the fly; for example, Yale should only beat Princeton in 59:41 fashion - not exactly a drubbing. Here's an Ivy+Stanford+MIT cross-admit comparison based on this data - http://college.mychances.net/tools/college-choice-matrix.php?list[]=342&list[]=544&list[]=3&list[]=1737&list[]=1519&list[]=165&list[]=1034&list[]=319&list[]=762&list[]=361 http://college.mychances.net/tools/college-choice-matrix.php...
- 16y ago
defen 16y ago
So is there a way to compute the probability of one team beating another, given their Elo scores?
- carbocation 16y ago
  It depends on their exact formula. Roughly, though: Probabilty of Team A beating Team B, given that Team A has 'A' Elo points and Team B has 'B' Elo points: 100/(1+10^((A-B)/400))
leelin 16y ago
Are today’s crop better players? Or like the economy, are Elo ratings subject to bouts of inflation? Players leaving the system is one of the major sources of rating inflation in chess. Even when rating changes of any single game is zero-sum, if a player stops playing chess after a career of net losses, all the remaining players in the world have more rating to divide up amongst themselves. This is very obvious on FICS bughouse where new sock puppet accounts crop up all the time, net lose several games, and then leave forever. Part of the problem is new players are usually given a starting rating around 1600 (depends on their provisional games), a "median" ranking of sorts, but in reality a new player is often far worse and donates rating as they slide down to their correct rating.
- carbocation 16y ago
  The last issue that you raised (new players donating ranking) has long made sense to me. However, I had not considered inflationary pressure due to players leaving before. Is the inflation really from their departure, or is it purely explained by their entrance, and loss of points while still playing?
  - s3b 16y ago
    Players leaving is a problem only if they lose points and then leave without winning them back.
- joe_the_user 16y ago
  In chess, constant progress is made in opening theory. Thus it is entirely plausible that today's players really are significantly better than those of 1979.
- joe_the_user 16y ago
  Stabilizing online ratings is difficult problem. In the game of Go, online ratings are general subject to deflation. New players appear, are given the lowest possible ratings and then rise to some higher ranking, knocking down the ratings of other players. Also, players who only play each other can improve together without any improvement in rating.
mollygray 16y ago
Hi everyone.... Playing games is the best entertainment for all.. Indoor games can be played by all kinds of people.. today, online games become more popular... Among them, shooter games have the rapid growth... They designed the gmes as per the users wish... http://www.puzzlebubbleshooter.com/bubbleblog http://www.puzzlebubbleshooter.com/bubbleblog
paulnelligan 16y ago
This looks like complete arse to me. 30 international games can span a 5-6 year period, during which time a completely new crop of players can emerge. Where does form come into the equation?, England's performance the other night was dismal, while Germany looked like potential winners. I've no clue how Mexico made the top eight, perhaps because they're based in Central America, and the competition isn't that stiff? And winners of the previous world cup, Italy, in behind them at number 8??? ... get real!!
- datageek 16y ago
  Good point on the 30 international games.
  - deleted 16y ago
    [deleted]
  - paulnelligan 16y ago
    I'm also bitter because Ireland aren't participating - eliminated by a Thierry Henry handball in the closing minutes of the second leg of the playoffs ... ouch!
deleted 16y ago
[deleted]
- datageek 16y ago
  From what I gather, these people aren't using Elo rating alone - it's just an "ingredient" in their model. Out of interest, did you enter the competition?
  - ulvund 16y ago
    No I didn't enter the competition I tried the different approaches on for predicting 10.000's of club matches and 1.000's of national team matches
lazyant 16y ago
A difference of two points in Elo is nothing; basically this corroborates the current betting odds that Brazil & Spain are the two favorites with small differences between them. In any case football/soccer results have such a big variance that it doesn't really matter. I think in HK there was a paper no long ago that studied soccer competitions and sayed something like the best team in a soccer competition only wins it a 30% of the time.
- alex_stoddard 16y ago
  A big variance is going to occur in any direct elimination competition (which the world cup is after the group stage). (This has always bugged me regarding the baseball playoff system. It is a big boost for teams economically but for purity I would prefer to see just a NL and an AL league table).

35 points by datageek 16y ago

Table tennis uses a similar system. My wife used to play competitively, and people at the club would always ask each others' ratings when looking for a good match. Of course, a single number can only tell you so much -- it's a very gross generalization of skill. A lower-score player can have a particular strength corresponding to another's weakness, thus leading to a win for the (generally) weaker player. I imagine that this is similarly true for soccer teams.

carbocation 16y ago
Absolutely. What you're describing is basically an interaction effect. Looking at all the data, A may be better than B by virtue of the fact that A is better than X, Y, and Z, while B is worse than them. But A has a specific weakness (an unprotected heel) and B has a rarely useful strength (ability to shoot arrows into the heel) that leads to B defeating A.
lotharbot 16y ago
> "Of course, a single number can only tell you so much -- it's a very gross generalization of skill." In a system where new players can enter after competition has begun (and others have accumulated points), there's also a good chance that a new player will not yet have had enough time to accumulate a score that's in line with their actual skill, which can lead to some misleading matchups. Depending on the details of the ranking system and the ease of finding similarly-ranked partners, it can take a long time to converge to a "true" rating. For example: I had friends in college who played competitive card games that had some sort of lifetime ranking (Bridge, perhaps?) Because they were young, they were often the lowest seed in tournaments. Despite above-average skill, they were normally eliminated by the very most skilled teams in the first round, and therefore had few opportunities to accumulate points against more equal competition. Once they finally broke through and won a couple of tournaments, there was a bit of a snowball effect as they moved out of the lowest seed.

carbocation 16y ago

Sweet. I love Elo points a lot (so much so that they are how my startup ranks U.S. colleges: http://college.mychances.net/college-rankings.php http://college.mychances.net/college-rankings.php ). The author poses the following question: "[...] like the economy, are Elo ratings subject to bouts of inflation?" Since the amount of points available depends on the number of individuals participating, Elo points should indeed be subject to inflation.

grasshoper 16y ago
Cool site. I knew Harvard's yield was higher than the other schools, but I didn't expect Stanford and Yale to have higher yields so much higher than Princeton. I don't think this was true a few years ago when I was applying to schools. How are you gathering information about where students were accepted? And where is Caltech in all this? Also, you know that you can't just add the 25th/75th percentiles for individual SAT sections and come up with overall results, right?
- carbocation 16y ago
  Thanks. Re: Caltech - if I recall correctly, there wasn't enough data for it to produce results when I ran the algorithm last year. I suspect we'll have enough this year (I'll probably re-run the algorithm in a few weeks). Basically the entire site is dedicated to gathering information from students, and then transforming that data into something useful for them. So I gather the info directly (over 250,000 college apps from 50,000 different people are in the system by now). I honestly have no idea why I thought I could get away with adding together the 25th and 75th percentiles for SAT subscores on that page; it's not something I do elsewhere on the site. (I'm using "I" here since I'm sure this is my fault alone.) Thanks for pointing that out! Edit: I forgot about Princeton. The Elo points can be a bit hard to decipher on the fly; for example, Yale should only beat Princeton in 59:41 fashion - not exactly a drubbing. Here's an Ivy+Stanford+MIT cross-admit comparison based on this data - http://college.mychances.net/tools/college-choice-matrix.php?list[]=342&list[]=544&list[]=3&list[]=1737&list[]=1519&list[]=165&list[]=1034&list[]=319&list[]=762&list[]=361 http://college.mychances.net/tools/college-choice-matrix.php...
16y ago

defen 16y ago

So is there a way to compute the probability of one team beating another, given their Elo scores?

carbocation 16y ago
It depends on their exact formula. Roughly, though: Probabilty of Team A beating Team B, given that Team A has 'A' Elo points and Team B has 'B' Elo points: 100/(1+10^((A-B)/400))

leelin 16y ago

Are today’s crop better players? Or like the economy, are Elo ratings subject to bouts of inflation? Players leaving the system is one of the major sources of rating inflation in chess. Even when rating changes of any single game is zero-sum, if a player stops playing chess after a career of net losses, all the remaining players in the world have more rating to divide up amongst themselves. This is very obvious on FICS bughouse where new sock puppet accounts crop up all the time, net lose several games, and then leave forever. Part of the problem is new players are usually given a starting rating around 1600 (depends on their provisional games), a "median" ranking of sorts, but in reality a new player is often far worse and donates rating as they slide down to their correct rating.

carbocation 16y ago
The last issue that you raised (new players donating ranking) has long made sense to me. However, I had not considered inflationary pressure due to players leaving before. Is the inflation really from their departure, or is it purely explained by their entrance, and loss of points while still playing?
- s3b 16y ago
  Players leaving is a problem only if they lose points and then leave without winning them back.
joe_the_user 16y ago
In chess, constant progress is made in opening theory. Thus it is entirely plausible that today's players really are significantly better than those of 1979.
joe_the_user 16y ago
Stabilizing online ratings is difficult problem. In the game of Go, online ratings are general subject to deflation. New players appear, are given the lowest possible ratings and then rise to some higher ranking, knocking down the ratings of other players. Also, players who only play each other can improve together without any improvement in rating.

mollygray 16y ago

Hi everyone.... Playing games is the best entertainment for all.. Indoor games can be played by all kinds of people.. today, online games become more popular... Among them, shooter games have the rapid growth... They designed the gmes as per the users wish... http://www.puzzlebubbleshooter.com/bubbleblog http://www.puzzlebubbleshooter.com/bubbleblog

paulnelligan 16y ago

This looks like complete arse to me. 30 international games can span a 5-6 year period, during which time a completely new crop of players can emerge. Where does form come into the equation?, England's performance the other night was dismal, while Germany looked like potential winners. I've no clue how Mexico made the top eight, perhaps because they're based in Central America, and the competition isn't that stiff? And winners of the previous world cup, Italy, in behind them at number 8??? ... get real!!

datageek 16y ago
Good point on the 30 international games.
- deleted 16y ago
  [deleted]
- paulnelligan 16y ago
  I'm also bitter because Ireland aren't participating - eliminated by a Thierry Henry handball in the closing minutes of the second leg of the playoffs ... ouch!

deleted 16y ago

[deleted]

datageek 16y ago
From what I gather, these people aren't using Elo rating alone - it's just an "ingredient" in their model. Out of interest, did you enter the competition?
- ulvund 16y ago
  No I didn't enter the competition I tried the different approaches on for predicting 10.000's of club matches and 1.000's of national team matches

lazyant 16y ago

A difference of two points in Elo is nothing; basically this corroborates the current betting odds that Brazil & Spain are the two favorites with small differences between them. In any case football/soccer results have such a big variance that it doesn't really matter. I think in HK there was a paper no long ago that studied soccer competitions and sayed something like the best team in a soccer competition only wins it a 30% of the time.

alex_stoddard 16y ago
A big variance is going to occur in any direct elimination competition (which the world cup is after the group stage). (This has always bugged me regarding the baseball playoff system. It is a big boost for teams economically but for purity I would prefer to see just a NL and an AL league table).