Vanderbilt's home field disadvantage, by the numbers

With Vanderbilt's diminishing football success as the 2017 football season unfolds, much of the spotlight has turned to diminishing fan support.

How bad is it, really?

And can we prove it's affected team performance?

Here's an honest attempt to answer those questions.

Vanderbilt still has a game to play at Tennessee, though it won't change the above numbers significantly.

VU's strength of schedule has been almost identical on the home and the road, so Vandy does appear to play slightly better at home.

But does Vanderbilt really have a home field advantage?

Or is it more of along the lines of, Vanderbilt isn't quite as disadvantaged because it's in someone else's stadium?

Oddsmakers have traditionally assumed a three-point advantage for the home team. "HFA" in the chart above indicates the average statistical value that mathematician Jeff Sagarin places on home field advantage across FBS and FCS games. Individual season numbers vary from 2.13 to 3.52, and the 2.79 above is an average.

If Sagarin's math is accurate, that means is there should be 5.6-point difference between home and road spreads. Instead, it's 1.8 for the Commodores.

Here's the math.

If Vanderbilt is 11.1 points worse than its opponents on the road, that means that it would be expected to be 5.5 points worse (11.1 - 5.6) that its opponents at home.

Instead, the Commodores are 9.3 points worse at home, implying that there's a 3.8-point home field advantage that's missing.

Take the math one step further, and it appears that the Commodores actually have a home field disadvantage of minus-1.0 points. (3.8 - 2.8).

I was skeptical of this. I needed to see how it worked at another SEC school.

I picked South Carolina, because its right in the middle in terms of stadium size (seventh in the SEC) and it was the closest school to .500 (.525) in conference winning percentage over the last year.

Whereas Vanderbilt's percentage differential in wins and losses at home and on the road is just 6.9 percent, it's an astonishing 32.8 percent for Carolina. The Gamecocks win almost twice as often on the road as they do at home.

Whereas there's a 1.8-point differential between home and road at Vandy, it's 8.5 at Carolina.

That's above the 5.6 that you'd expect, all things being equal.

In this case, all things aren't equal.

Whereas there was no difference in Vandy's schedule home and away, Carolina's schedule away was a bit tougher, which may explain some of the reason the number was higher.

I'd have to look at more teams, something I don't have time to do right now, to see if this is an extreme example.

But if what you see at Carolina is in line with what you see everywhere else, Vanderbilt is at an enormous disadvantage when it plays at home compared to the rest of the conference.

Now, let's look at Vanderbilt's attendance figures:

The overall figures aren't as bad as you'd think. But two things:

1. They're falling. Even in the three years before, between 2005-07 respectively, Vanderbilt drew crowds of 34,629, 34,861 and 36,031. None of those teams had winning records.

2. They're increasingly made up of visiting fans. Vanderbilt fans were out-numbered by Alabama, Georgia, Kentucky and Missouri fans in the four SEC home games this year. The Kansas State game was said to be close to 50-50. Memory sometimes fails, but VU was close to outnumbered (or maybe was outnumbered) by Tennessee and Ole Miss last year. I think Florida fans outnumbered Vandy fans in Vanderbilt Stadium last year, though Vanderbilt clearly did have an advantage in the South Carolina game.

At best, Vanderbilt has been out-numbered in its own stadium five times in eight conference games over the last two years. At worst, that number was seven.

The numbers tell the story, but so does the picture below, shot at the beginning of the second half of last Saturday's Missouri game. The largest population of fans was across the stadium where Missouri fans congregated.

The numbers and the pictures are clear: Vanderbilt has a financial problem and a performance problem related to its inability to put its own fans in its own stadium, and it's getting worse. It's a problem in no small part created by administrative neglect, and its time for Vanderbilt's administration to make a real effort to do something about it.