How your team color relates to the odds of the game outcome in Ranked MM.

The numbers were something like 52% of a win for red, 48% for blue.

 

Good theory. Makes a lot of sense, too. I wondered why mmy skill wouldn't go up; I kept getting put on red team. I would win 5 matches in a row and my skill wouldn't move. Then I'd lose one match (but come first in my team) and my skill would go down.