Author: Bob Durrett
Date: 16:24:16 01/05/04
Go up one level in this thread
On January 05, 2004 at 19:17:04, Christophe Theron wrote: >On January 05, 2004 at 16:50:03, Bob Durrett wrote: > >>On January 04, 2004 at 23:04:55, Christophe Theron wrote: >> >>>On January 04, 2004 at 11:10:41, Bob Durrett wrote: >>> >>>>On January 04, 2004 at 11:00:31, Dan Andersson wrote: >>>> >>>>> I admire your persistance. I guess most of us that have a mathematical >>>>>statistics education got tired explaining things after the first thread or so. >>>>> >>>>>MvH Dan Andersson >>>> >>>>I, too, have a "mathematical statistics education." >>>> >>>>What bugs me is that all of the CCC bulletins seem to suggest that those who run >>>>and evaluate tournaments look only at the win/loss statistics. There is >>>>considerably more information in a game score than just the final game result. >>>> >>>>Throwing away useful information is what I call "blind adherence to statistics." >>>> One needs to rise above one's formal education and supplement it with good >>>>thinking. >>>> >>>>: ) >>>> >>>>Bob D. >>> >>> >>> >>>The games themselves do not contain more information about the relative strength >>>of the opponents than the bare winning percentage of the winner. >> >>I would like to try to offer a counter-example: >> >>Suppose there is a match between two chessplayers, A and B. [human or >>otherwise]. Suppose also that N games are played in the match. >> >>In this example, endgame of type #1 will occur in the match a finite number of >>times, assuming that each game in the match has a finite number of moves. >>[Adjudicate after 60 moves]. >> >>If endgame of type #1 occurs rarely in practice [as seen in a much larger >>collection of games such as Megabase 2004], then the best estimate of the number >>of times that type of endgame would occur in this match would be small, likely >>much much smaller than N. However, suppose an uncharacteristically large number >>of occurrences of endgame type #1 occurred in this particular match. >> >>Suppose also [since I'm the one dreaming up this example] that every game in >>which endgame of type #1 occurred, chessplayer A handled that endgame properly >>but chessplayer B obviously didn't have a clue about how to play that endgame. >> >>Then post-mortem analysis would have to conclude that in a more normal sample, >>where the number of occurrences of endgame type #1 were more typical, the >>percentages of wins and losses might be different, becoming more favorable to >>chessplayer B. [Chessplayer B was handicapped by the abnormal number of >>occurrences of endgame type #1 which chessplayer B cannot play well.] > > > >There is no reason to assume that... Please clarify what you mean. I do not understand. There is no reason to assume . . . what? Bob D. > >If you start to assume this or that, we are not talking about a measure anymore. > >A measure of the elo difference between two players does not involve anything >else than the number of wins, draws and losses. Or the winning percentage. > >The information contained in the games themselves can be used for many things, >but not to fix the measure of the elo difference... > > > > Christophe > > > > >>Since "ratings" are merely estimates of performance, then the information >>relating to endgame type #1 in the match could be used to obtain a better >>estimate of the ratings or, in this case, the relative ratings. >> >>Generally, the more information that is available, the better can be the >>estimates. Obviously, the information must be used properly. >> >>- - - - - - >> >>Incidentally: During post-mortem analysis, tens, hundreds or even thousands of >>opening, middlegame, and endgame "types" could be identified in the games of the >>match and the same comparisons made with a large population. Doing so would >>permit a better estimate of the ratings or rating difference. >> >>- - - - - - >> >> >>Bob D. >> >> >>> >>>That should not be forgotten. >>> >>> >>> >>> Christophe
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