Sorry I missed you -- fell asleep. Oh well... In any case, Nick15's rating kamikaze seems to show that there is, indeed, some bias for lower-ranking players (as all of his losses seem to give more to the opposing player even for less substantial wins) (also, it seems that the change becomes less signaficant later on, but rating kamikaze is hard to do like this since you can only do it for about 10 games)
Could there be a bias of larger movement for players who haven't played much (few games, or few wins)? If so, that would correspond to "provisional" Elo rating.
It's clear that you get fewer points per win if you have a high rating. One thing I've been trying to figure out is how points per win scale with your rating. As I mentioned, some guy with a near-8000 rating played me when I had a near-7000 rating, and gained 2-3 points per win. When I reset my rating to 5000, I played someone with a near-6000 rating, and let him win; he gained 24 points for that win. (At one point I had my rating down to 4000, but I couldn't match up with any near-5000 players.) There's probably some sort of exponential scaling going on, but we'd need a few more data points to be sure. It'd have to be something along the lines of "points earned decrease by a factor of 3 as the winner's rating increases by 1000". I don't think there's a provisional rating, exactly; I think you just naturally get many more points per win when your rating is low. I also spent a while gathering data on matches where my rating was near 5000, and I won. I spent a long, long time trying to figure out the formula for rating changes with the winner's rating fixed at 5000, and didn't get anywhere. I can say, however, that it doesn't feel like an ELO-style system. (I was thinking that it might be just the ELO system, except with K as a function of the winner's rating, not a constant. No such luck.)
I can say now with more certainty that there (probably) isn't a provisional rating system for new players. I reset my data, won a lot, then lost my way back down to ~5000. I went about 55-55 (so over 100 games). I played one more game (my rating was 5055, his was 5180) and gained 78 points, which is in line with the data I posted in the other thread.
Just as a general question, I take it no one has yet worked out any sort of algorithm for the Wifi rating system?
It's hard to be accurate -- there's an unknown even in ratings (the decimal), and there's no way to fix this outside of getting the values straight from the Nintendough servers.
