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Subject: Re: Have any Studies been done to in relation to Time control and Chess Stre

Author: Tim Mirabile

Date: 14:53:49 05/11/99

Go up one level in this thread


It's important to understand that a chess rating does not correspond to some
absolute level of playing strength.  Humans play weaker chess (i.e. weaker moves
in an absolute sense) when there is less time to think, and so do computers.

When humans play in action chess events, they usually play other humans, and on
average, the various playing strengths of human players drop at roughly the same
rate as the time control gets shorter.  So two humans who are 2300 at slow time
controls will probably be roughly equal (+/- 50 points) at action chess.  Since
chess rating scales are arbitrary, an effort has been made to make human rapid
ratings conform roughly to human slow time control ratings.

Computers, on the other hand, do not drop in strength nearly as rapidly as
humans do when the time control is shortened.  So for a human and computer who
are about equal at 40/2, playing at G/30 the computer will seem much stronger
relatively, and calculating a rating for the computer at this time control using
the humans slow time control rating will result in a very inflated rating
relative to the human's slow time control rating.  The amount is surely
dependent on the hardware speed of the machine, with faster hardware machines
decreasing less in strength with faster time controls than slower machines.
This is due to the exponentially increasing time needed to search an additional
ply as you get deeper in the search, along with the diminishing returns of
searching that additional ply.

This is why it is misleading to use G/30 results to rate chess computers (common
with dedicated chess computers).  True, most people probably do play against
these computers setting them at a rate of play roughly equal to action chess,
but they don't force themselves to play under the same time limit (or under any
time limit at all).  So what you get is a computer rating which is very inflated
compared to the human's slow time control rating, plus the fact that the machine
is essentially giving time odds. The result is that machines played under these
conditions are not anywhere near as challenging as the G/30 rating would make it
seem.

On May 11, 1999 at 07:26:52, odell hall wrote:

>Hi CCC
>
> I have heard many  people say that computers would lose if the time control
>were slower, for instance this match with Gelfand. I know that among humans a
>person rated 2300 at action chess, will be around the same, or within 50pts at
>40/2.
>What evidence is there to suggest that a computer that plays at 2800 level at
>action will play 300 or more pts weaker at 40/2 ?  I believe I rememberLarry
>kaufman saying that the actual difference between action and 40/2 chess was
>about 85 pts for computers, although I do not remember what his evidence to
>support this was.



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