Tuesday, November 6, 2007

The Value of Homefield Advantage 2007 Week 9

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).

HFA has regressed over the last couple of weeks, but divisional games have still been a disadvantage for the home team by a wide margin.

All Games
Home Team Win %: 56.1538%
Avg. Final Score Margin: 2.2538

Home Team Win %: 61.5385%
Avg. Final Score Margin: 4.6154

Interdivision, Intraconference
Home Team Win %: 65.2174%
Avg. Final Score Margin: 3.9130

Home Team Win %: 42.2222%
Avg. Final Score Margin: -1.4889

1 comment:

Michael Lestyk said...

I think you are going about it wrong. If you want to analyze HFA, you should look at individual cities and come up with HFA plus-ups by stadium. For example, Indy's dome produces more noise than other venues. This extra noise causes more false starts and messes with audibles than other venues. Some teams are farther away, on average, like Seattle, and may cause more jet lag in visiting teams. Some crowds pump up their team more - I'm thinking of Denver.

All you need to do is run a comparison of pts for and against per team away and home. The average difference is the expected advantage of the home field.

Thanks for the blog. Keep up the good work. Also, check out www.footballoutsiders.com, if you haven't already.