Citation needed. I read that they changed premade ELO adjustments to be negligible for bad players and high for good players. This was like a year ago or around that.
Well, my citation is an email sent to me by Tom "Zileas" Cadwell. I've talked to the Riot guys quite a bit, they actually play our Facebook game. I even got to check my elo :)
He didn't get into too great detail though so it's possible I misunderstood and it actually is a sliding scale, though I've seen no evidence of that (and quite a bit of the opposite).
"This bonus is calculated from a bunch of research we did on hundreds of thousands of game results to figure out how much of an advantage being in a team is. We do some behind the scenes adjustments as well for stuff like beginners paired with pros, etc."
Personally, the matchmaking seems to me to get better and better the more players pick up the game. I still see unbalanced games, but I can't remember the last legitimate curb stomp, where one team was simply outclassed...
He didn't get into too great detail though so it's possible I misunderstood and it actually is a sliding scale, though I've seen no evidence of that (and quite a bit of the opposite).