Refs, jet lag and color red all contribute to home-field advantage

It's that time of year. NFL teams have battled all season to secure home-field advantage in the playoffs; now, the best squads in the league get to enjoy the comforts of friendly turf. Coaches, athletes and sportswriters all make a big deal about the benefits of home. And fans bring what they can to sharpen their team's edge: face paint, rally towels, lots of screaming. There's a shared glory in being the 12th man.

But is the glory deserved?

Intuition is one thing; actual evidence is another. If the most rabid fans -- like the Cameron Crazies, for example -- give their clubs the biggest boost, then why do teams from the unassuming Mountain West enjoy the largest aggregate home-court advantage in Division I basketball? And if superstars gain an intimidating edge at legendary venues (think Brett Favre at Lambeau Field or the Murderers' Row Yankees), how is it that the wretched 1945 Philadelphia A's, who played in the now-forgotten Shibe Park, still own baseball's greatest home-field advantage of all time (.527 at home, .171 away)? Do teams play better at home because fans support them so strongly, or do fans root harder for teams that win?