[rjp]

It's good that you realize home field advantage isn't something you can express as points (especially in football), as the numbers just don't add up right. In some cases you're giving too little and in others too much. Taking this a step further and treating all games as a winning percentage and you should be able to quantify home field advantage much better than the average Joe.

That said, home field advantage isn't something I've studied all that deeply. What I do know, however, is that it might bet better to look at it as away team disadvantage. Traveling and staying in hotels in an unfamiliar place takes its toll. It isn't always about how loud the home crowd cheers (or boos)....