Author: Dann Corbit
Date: 19:45:41 06/15/01
Go up one level in this thread
On June 15, 2001 at 22:23:38, Mark Young wrote: >Nothing more really needs to be said, but you guys can debate more among >yourselves. To restate no ratings system is absolute the rating numbers be it >2500 or 3000 mean nothing in themselves. What is important is the difference >between two ratings in the same ratings pool. Anyone knowing how ratings work >would never bring the word absolute into the discussion as Bob has done. > >Ratings and whichever system is used to calculate the numbers are simply a >measure of dominance in the ratings pool. If the system is working correctly it >should be able to predict with a high degree of certainty the outcome of a >series of games between two players in the same ratings pool. Even if the >players have never played each other before. > >The problem with discussing this issue is some do not understand what ratings >are, and how they work. As when Bob stated all players in the ratings pool must >play each other a equal number of times for the rating system to be accurate. >This is just incorrect. Thing start to become more ridiculous from there. It's an overstatement. We could say more accurately: "The more players in the same pool play against each other, the more accurate the ratings become." Or, equivalently: "If a player has had few games against a pool of rated talent, the calculation of ELO for the new player will have an enormous error bar." What is *not* meant: "12 players all played each other exactly 2 times. Therefore, their ratings are more accurate than the pool where people played each other somewhat random numbers of times, but at least 500 times each." This part of the problem really can be deduced using nothing more than common sense. Where do problems arise? The Burmese (Myanmar) FIDE ratings scandal is a case in point. Players isolated from the pool do not have comensurate meaning when we try to compare the ratings. I don't think for a minute that people were cheating (though it isn't impossible). Rather, the pools of players were isolated. It should have been rather more astonishing if two dissimilar pools produced ELO rating scales that were identical! Or when people try to figure out things like Paul Morphy's ELO because A played -> B who played -> C who played ->D etc. It doesn't work that way.
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