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Ratings correlation between ICU/FIDE?

  • 22-01-2021 7:02pm
    #1
    Registered Users Posts: 2,703 ✭✭✭


    First off, I know this shouldn't matter to me... but I think it is interesting!

    https://chessgoals.com/rating-comparison/ has a comparison between chess.com, lichess, USCF and FIDE ratings.

    I notice the brilliant ICU website has the FIDE rating of all ICU rated players, so does anyone know if they've done a correlation between the two?

    If not, is there a data dump of ratings and I can do it. I doubt there is so I might do a data scrape of the ICU ratings, but they might not be too happy with that.

    I've always noticed that ICU ratings, especially in the lower levels where I am, are much stronger than you'd expect from an equivalent USCF rating.


Comments

  • Moderators, Sports Moderators Posts: 7,117 Mod ✭✭✭✭cdeb


    You'd need to be careful of FIDE outliers - those who've only played a few FIDE-rated games and whose FIDE rating wouldn't reflect their real strength anywhere near as well as their ICU rating.

    A data scrape would be easy enough off ratings.icu.ie and the FIDE ratings site, but less so off lichess, where you don't necessarily know who everyone is. It'd be interesting though.

    As a general rule, and below title level, you can add 100 points to an ICU rating to get the equivalent FIDE strength.


  • Registered Users Posts: 2,703 ✭✭✭MyPeopleDrankTheSoup


    Don't think I need to scrape off lichess, they've an API: https://lichess.org/api. I'm not certain they just give out the whole user database but chessgoals seems to be able to do it: https://chessgoals.com/rating-comparison-explained/

    But I wouldn't be doing that anyway, I'd just compare ICU and FIDE.

    Yep, outliers are a problem in all rating systems I think, that's where Lichess use Glicko and give you a ratings deviation to tell you how confident they are.


  • Registered Users Posts: 259 ✭✭RooksPawn


    Comparing online blitz/rapid ratings with FIDE classical ratings is pretty pointless, especially as most people have not been able to play a FIDE rated game since last February (or even earlier).
    In the meantime juniors and people who play online a lot have probably improved their play and everyone else will have declined, though we won't know who is which until regular OTB restarts,
    Comparison with FIDE blitz and rapid ratings might have some point but ICU only has classical ratings.
    I suggest you could find a better use of your time.


  • Registered Users Posts: 3,863 ✭✭✭mikhail


    I remember a statistical analysis published maybe 20 years ago that made a comparison of FIDE and ICU ratings, and argued there wasn't enough difference to merit any action. I forget the details, but perhaps Vincent Bissett was involved.

    The FIDE rating floor has dropped dramatically since then, and I don't know if there've been enough FIDE rated games in Ireland to consider the FIDE ratings of players below 2000 (or 1800 anyway) settled enough to merit comparison. In any case, there's not much point in getting worked up about different systems showing some differences. As Rookspawn says, there's even less point comparing online blitz ratings with ICU classical ratings: it's a completely different shark.


  • Registered Users Posts: 1,297 ✭✭✭sodacat11


    mikhail wrote: »
    . As Rookspawn says, there's even less point comparing online blitz ratings with ICU classical ratings: it's a completely different shark.
    I completely agree, that is why I hate having classical chess events decided by blitz or rapid games in case of a tie. If four players tie in a tournament like the Tata Steel or the Irish Championship then they all deserve the title. A blitz or rapid game will favour the higher rated player, and usually the younger player, yet the lower rated might have had a far more noteworthy performance and a much better rating performance to tie in the first place.


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  • Registered Users Posts: 2,703 ✭✭✭MyPeopleDrankTheSoup


    I attempted this ICU to FIDE thing but then I realised I don't have a clue about stats. I don't know if it can work at all. I got FIDE ratings from their site and the scatterplot was all over the place until I limited FIDE ratings of less than 40 k-factor, so usually that means they've played at least 30 FIDE rated games. Now it kinda looks sane. Some serious outliers there that I'll take out later.

    1YJJQ2E.png


  • Moderators, Sports Moderators Posts: 7,117 Mod ✭✭✭✭cdeb


    So this seems to broadly corroborate the view that ICU + 100 = FIDE?


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