What does it mean to say a player is "performing at such and such rating"?
Well I figured as much, but how do they calculate it and how does it affect his actual rating?
An equivalent, and perhaps simpler arithmetically, formula is to take the number of wins minus the number of losses times 400 plus the average opponent rating (for all games including draws).
(W-L)*400 + Average_opponent_rating
Or to put it in words, it means that Ivanchuk is peforming as well as a player with a rating of 3150 would be expected to perform. ie, he is performing very well
I read online that right now Ivanchuck is performing over 3150 in his currant tournament. What does that mean?