Author: Drexel,Michael
Date: 05:23:22 12/02/04
Go up one level in this thread
On December 01, 2004 at 23:25:29, Ricardo Gibert wrote: >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. The outcome of such a 100 games match between lets say a 2200 rated player and a 2300 rated player is not at all determined. First of all ratings are very often not accurate. Even if we assume they are (both players achieved their ratings against the same opponents with a significant number of games) the higher rated player of course does not necessarily win such a match. For example: The 2300 player might be an agressive player and strong tactician with lots of risky and objective unsound variations in his repertoire. As a consequence he scores very well against <2100 rated oppponents. The 2200 player might prefer a calm positional style and play the opening accordingly. As a consequence he often has to be satisfied with draws against <2100 opposition. Michael >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.
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