Quote:
Originally Posted by Dire
Ok, yeah. That makes more sense. I was not explicitly considering the fact that he was 2700 getting the handicap. But I don't know. Somehow something still feels a little bit off saying +1 =5 -2 with the only win coming from a no handicap game (=4 -2 in handicap games) is a 3000+ performance.
"Performance rating" is a somewhat nebulous concept in general. Performance rating over a short match or tournament can vary wildly from "actual playing strength". Even if this is accurate, it certainly doesn't prove anything about Rybka's playing strength.
That being said, the only nebulous part is estimating the value of the handicaps. If 50, 450, and 500 are valid, Rybka actually performed BETTER in the handicap games. Playing as black, Rybka scored 1.5/2, or 75%. By definition in an Elo system, scoring 75% means you are 193 rating points better than your opponent, so if we accept the premise that Milov with white is a 2755 (50 point handicap) then Rybka's performance rating for those two games was 2948. In the handicap games, Rybka scored 2/6, or 33%, which by definition is a performance of -125 points. If we accept the premise that Milov with the handicap is 3155-3205 (450-500 point handicap), then Rybka's performance there is over 3000 (3046, to be precise).
Here are full Elo percentage score to rating difference tables. Feel free to double check the math if you're still unsatisfied.
Now of course, it might just be variance and Rybka may have overperformed (a score over 3000 isn't unheard of for humans over a short stretch either.
See Ivanchuk's 3537 performance rating through the first five games of MTel Sofia 2008.). Additionally, the handicaps may be inaccurately valued here, the numbers are very rough. Is Rybka actually a 3000+ caliber player, expected to score 80%+ against a world champion human? I don't know. But the performance rating here is valid, as long as you accept the assumed handicap values.