Zarkon wrote:Peter C wrote:Chris Whittington wrote:Does anybody have a proof that rating list ELO correlates to chess playing skill?

Or that the relationship between rating list ELO and chess playing skill is in any way linear?

Why wouldn't it?

No, it's logarithmic. The strength difference between 3000 elo entity and 2900 entity is greater than the difference between 2500 entity and 2400 entity.

Peter

Are you sure? I thought a 100 Elo difference would mean that one player would score x% against the other, regardless of where it sits on the scale.

yup the elo formula its not logarithmic but linear , from wikipedia :

"Elo gives an example of calculating the rating of Lajos Portisch, a 2635-rated player, in an actual tournament of 16 players, and scored 10½ points. First the difference in rating is calculated for each other player, subtracting the other player's rating from Portisch's rating. Then the expected score against each player is determined from a table, based on this rating difference. For instance, one opponent was Vlastimil Hort, who was rated at 2600. The rating difference of 35 gave Portish an expected score of 0.55. The expected score is summed for each opponent, giving Portisch a total expected score of 9.66. Then the formula is:

new rating = old rating + K×(W-We), where K=10, W=actual score, and We=expected score.

So 2635+10×(10.5-9.66)=2643.4, Portisch's new rating "

so u can see that the elo rating difference is the key and not how much high is the elo