User blog comment:Fistful of Force/LoL Macro: Death by numbers/@comment-216.36.26.248-20130321203937

You misread an important part of Kronen's findings. It wasn't 7% over the course of the game, it was that the winning team at no point was more than 7% behind the losing team in gold. This means that, even after losing a team fight, they were still within 7% of their opponents' gold totals.

And this makes sense. Losing a team fight 5-0 pretty much guarantees at least two towers and a considerable difference in gold immediately afterward. Subsequent team fights become even harder. This doesn't even account for the psychological blow. Losing a team fight 4-3, though, keeps you in the game and preserves your base for just a moment longer.

I've already seen this subverted a few times in Season 3 though. One team was behind approximately 15% on gold and after two disastrous team fights was ahead and won the game. This may be an outlier though, as the season progresses more information will come to light.