Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Human rating differential compared to Computer vs. computer

Author: Dann Corbit

Date: 18:12:58 01/29/99

Go up one level in this thread


Consider a 300 point difference in a 20 game match between a 2800 SGM and a 2500
GM.  There are 20 points at stake.  The win expectancy is .15, so .15*20 = 3
points gathered by the 2500 GM expected.  So perhaps, one win and four draws
would be expected in a 20 game match, roughly speaking.  Now with a 500 point
difference, the expectancy is now .05, so .05*20 = 1 point, perhaps two draws
against a 2200 player.  18 wins and two draws or 19 wins and a loss is pretty
much complete domination in a twenty game match.  Now, if you go to your chess
database and pick some very prolific super GM like Spasski, you will find that
every so often he does lose to someone you have never heard of.  But now, let's
suppose that the difference was 1000 points (As if a 2800 player playing an 1800
player match of 20 games would be held).  The expectancy is 0.00315231, so in 20
games this gives .06 points.  In other words, if they played 200 games, the 1800
player might somehow get a draw.  But in a 20 game match, we would be very
astonished if the 1800 player even drew a game.  And in a 200 game match we
would be very surprised if the 1800 player won a game.  Now  It sounds pretty
absurd, doesn't it -- in 400 games the 1800 player would win one, on average (or
get 2 draws)?  But that is because we may be thinking that "1800 is 1800" when
in fact that does not need to be the case.  Tal, Karpov, etc. were all 1800
players *at some time* and rising rapidly.  So now you see *how* these 1800 ELO
players will win against the big fish.  A lifetime 1800 player is basically
*never* going to win without a stupendous blunder, and even with the blunder it
is not assured.  So why don't we have lots of wins over GM's by 1800 players?
Because once you beat up a few GM's you don't stay at 1800 any more.

Certainly the bulk of the wins by lower rated players against those much higher
will be by players on the way up against players on the way down.



This page took 0.01 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.