I just lost rating points with a win against a player rated 500 points lower than me?!
This was on the ICC, not here - I'm just curious about the math behind it, not complaining. Doesn't make a lot of sense to me, but I might miss something.
Imagine that your rating was calculated by the last 100 games and you get (opponentrating x 1) points for a win and (opponentrating x 0,5) for draw and (opponentrating x 0) for a loss. We guess that the very first of these last 100 games was a win against a strong player and it will now be replaced by this win against a weak player. Now you win these few points from the weak player but you lose these many points from the win against the strong player you played 100 games ago. So on the whole you lose some points.
This is a very simple example how it COULD work. You maybe can compare it to the FIFA world ranking system. It's working nearly the same way.
You should score 95% with a difference of 500 points. This I think means if you played a 100 games, you'd win 95.
http://en.chessbase.com/post/the-elo-rating-system-correcting-the-expectancy-tableshttp://www6.chessclub.com/help/ratingsthere is all you need to know about ICC ratings. and even the "loss of rating points by beating a much weaker player" is described
Thanks for the link, #4.
Indeed my rating was provisional, I was playing the relatively new 25+10 pool.