I’ve spent a fair amount of time over the years thinking about home field advantage in football. It’s a complex, and real, phenomenon. It is not uniform, and it may change from week to week depending on things like the opponent and their familiarity with your venue, the particular strengths and weaknesses of both teams, weather changes (when applicable), and yes, even the officials.
The impact of the officials, though, has been relatively small in the NFL, at least compared to some other sports like basketball. I’m not saying it doesn’t exist or occasionally there aren’t calls in favor of the home team–just that they make up a fairly small portion of the broad concept we call home field advantage in the NFL, probably no more than 15%.
My interest was piqued, though, by a couple of observations by Chase Stuart of Football Perspective this week. First, he notes that 14 of the 16 home teams won this week, the first time since the league expanded in 2002 that many home teams have won. Second is the discrepancy in penalties called on the road and home teams through two weeks of these replacement officials.
So far this season, there have been 231 penalties against visiting teams and only 188 penalties against the hosts. That ratio — road teams having to deal with 23% more penalties — is far out of line with historical data, which informs us that road teams had 7% more penalties enforced against them than home teams from 2000 to 2011.
One of the areas where we might surmise that inexperienced officials might be affected is by crowd influence. This could be particularly true for those coming from situations with much smaller home fields, and we know that these officials by and large are not coming from the FBS level of collegiate officiating.
So, I dug a little further, to look at home field advantage through the first two weeks.
So far this year, the home teams are 23-9 (72%). Here is a comparison to the home records in the first two weeks for the last decade.
Two years have seen 21 home wins in the first two weeks. The average is 18.4 wins. Not all home games are created equal, though, so perhaps this variation is based on specific home teams. One way to account for this is to look at the Vegas spreads. Using data from goldsheet.com, I compared the previous three seasons against the spread to this year. This was done by comparing the actual result to the spread to see how much better or worse than expectation each home team did. There are extreme results, so we will use the median data.
Here is the against the spread records and median points above or below the spread for the home team:
- 2012: 19-13 against the spread, +5.3 points over spread for home team
- 2011: 16-15-1 against the spread, +1.5 points over spread for home team
- 2010: 19-11-2 against the spread, +3.8 points over spread for home team
- 2009: 12-20 against the spread, -4.8 points under spread for home team
Combining all three previous years, we get a home team ATS record of 47-46-3, with a median result of a push. So basically, Vegas has been dead on with variation from year over year. Maybe this year is just another case of random variation, though I think there are legitimate reasons to think that it is more than that.
So far, in order to get an even betting result of point spread wins by home teams and road teams, Vegas would have had to add a whopping 5.3 points to each spread to the home team’s line. They already build in somewhere around 2.5 to 3 points for home field in matchups, meaning Vegas would have had to add about 8 points to home field to even out the replacement referee results. How will the market react to the referees this week?
The NFL has had a love/hate relationship with sports wagering, pretending to be against it at certain times while benefitting from its impact on the product’s popularity. Vegas insiders have to be concerned about these results through two weeks, and how it affects the market view on home teams. Much discussion has been about the integrity of the game, a lot of it focusing on injuries. A potentially undervalued angle is the impact on home field advantage. A team with a front loaded home schedule may be enjoying an advantage if the league settles with the normal officials before season’s end. We may also see this effect diminish, even if it is real, as the officials become more experienced in handling crowd input. Thus, getting to start at home, particularly in an important game, may not be such a bad thing.
[photo via US Presswire]