The Value of Homefield Advantage 2007 Week 12

One of the things I've learned in my football research is that the value of home-field advantage varies pretty widely from year to year, especially with interconference games. Because prediction systems tend to have a big bias towards the home team, this can have a large impact on accuracy. So throughout the season, I'll be keeping track of home team winning percentage and average final score margin (home team points - away team points) for interconference, interdivision, and intradivision matchups. If you're interested in that sort of thing, it can help you with betting on the spread (hint).

I am completely baffled about the divisional games.

All Games
Home Team Win %: 55.1136%
Avg. Final Score Margin: 1.6932

Interconference
Home Team Win %: 62.5000%
Avg. Final Score Margin: 4.3750

Interdivision, Intraconference
Home Team Win %: 69.8413%
Avg. Final Score Margin: 4.6032

Intradivsion
Home Team Win %: 35.3846%
Avg. Final Score Margin: -3.1077