Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Elo-related question, how to rate puzzles?

Author: Ricardo Gibert

Date: 20:25:29 12/01/04

Go up one level in this thread


On December 01, 2004 at 17:37:39, Andrei P wrote:

>in Livshitz book "Test your chess IQ first challenge", which test human tactical
>skills, he gives a table that shows a correlation between % solved and elo
>strength.  To create the table, the author tested the tactics in the book on
>humans with known elo and and then fitted the data into the table (see below).
>
>% solved   elo
>100%	   2200
>90%	   2000
>80%	   1800
>70%	   1600
>60%	   1400
>50%	   1200
>
>I thought that, in general, one should be able to treat puzzles like players of
>a given strength. The stronger the puzzle,the higher its  "elo". so one gets
>higher elo performance by solving higher rated puzzles etc. But according to
>this table, the puzzles do not behave like human players. For example, one could
>surmise that the average elo of the puzzles in this "tournament" is 1200 (humans
>with 1200 elo solve 50%), so according to fide expactacy, a 1600 player should
>score 92% against opposition of 1200, but scores only 70% in the table.
>
>What is the reason that relation between % solved and elo is different than for
>human-human matches? if anybody has references to how puzzles are rated that
>would be great.
>
>Thank you, Andrei

You've assumed that the rating that corresponds to a players ability to win
games corresponds exactly to that of his ability to solve positions. Bad
assumption.

To see why this is significant, replace the solving of positions with the
winning of a chess match. The outcome of a 4 game match is pretty random even
when the participants are rated 100 rating points apart, but if the match is 100
games long, then the player with the rating advantage will have a virtual lock.
It is evident that a players ability to win an individual game does not
correspond directly to his ability to win a long match.

Similarly, a players ability to solve an individual position does not correspond
directly to his ability to win an individual game.

There is some relationship of course. The favorite is still the favorite, but
the percentages will not remain the same. They have to be scaled by an
appropriate function.



This page took 0 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.