Author: Robert Hyatt
Date: 20:19:53 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 is not incorrect. Go pick up _any_ book on sampling theory and give it a read. I gave an example of why your statement above is _wrong_. Take a group of 20 players. players 1-10 play each other all the time. Players 11-20 play each other all the time. Comparing ratings for the 1-10 group will give a very good prediction of how they will do in a game vs each other. Same for the other group. But then use those ratings to predict the outcome for player 1 vs player 20. Won't work. If you have one player from the first group that plays one player from the second group a lot, that tries to "couple" the two pools. But not very well. However, if _everybody_ plays _everybody_ then you can predict the outcome of any two players pretty well. That was what I said. That is simply fact. Which means you can not predict ratings for players that played before a formal rating system was in place. Any more than you can compare a player of today with a player from 40 years ago and use their ratings to predict how a game between them would turn out. I don't see why this is so hard to follow...
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