For Vanderbilt, rushing defense has been highly correlated with winning.
Something new I decided to do for this year's set of previews is run correlations on various statistics and each team's winning under their current coaches. The idea is to see what matters most to their style of play and ability to win. I used the NCAA stat archive and calculated correlations for both the raw numbers and the team's national ranks. When compiling the results for the tables, I list only one or the other according to which has the stronger correlation.
For Vanderbilt I can't really do it based on James Franklin's tenure there, so instead I used the Bobby Johnson/Robbie Caldwell era of 2002-10. These are the strongest indicators of winning during that time:
|Total Defense Rank||-0.649|
|Scoring Defense Rank||-0.598|
|Passing Efficiency Defense||-0.483|
|Yards Per Carry||-0.338|
|Kickoff Return Yardage Rank||0.280|
The cut off of notability I used for strength of correlation here is 0.264. Why? That's the correlation of games played with winning percentage. If a stat can't beat out games played for correlation strength with winning, then it probably wasn't a strong factor.
What's not surprising is that most of these have to do with defense and turnovers. Vanderbilt's modus operandi has generally been using a tough defense to make up for a bad offense. Also, it must get turnovers to have a chance at beating more talented teams, so it's not a surprise to see turnovers gained on there. When the Commodores lose the turnover battle, they have little chance to win as the perennial underdog, so turnover margin makes sense. The strongest offensive mark is scoring offense, but keep in mind that "scoring offense" includes return and defensive scores as well.
That rushing defense is way up there is no surprise at all. It's not that Vandy's best chance to win is to stack the line; rather when the team is bad and falls behind early and often, opponents tend to run the ball to avoid being accused of running up the score. When Vanderbilt is not giving up lots of rushing yards, that generally means it's in more games than not.
The most interesting result here for me is that rushing offense has a decided negative correlation. That indicates that as rushing yards go down, winning percentage goes up. I can tell you why the numbers ended up that way: Vandy wasn't prolific at rushing the ball in 2005 (115.09 YPG, 5-6 record) or 2008 (133.62, 7-6), while it had higher outputs in 2002 (173.5 YPG, 2-10) and 2009 (160 YPG, 2-10). In 2005 the lower rushing amount was a factor of Jay Cutler excelling at throwing the ball, but the same couldn't be said of the dreadful 2008 passing attack.
My best guess is that it's just some kind of quirk of the numbers, especially given that total offense (-0.031), total offense rank (-0.200), passing efficiency (0.064), passing efficiency rank (-0.010), and to a lesser extent rushing offense rank (0.379) all had much weaker correlations than rushing offense alone did. Even so, yards per carry also had a negative correlation with winning, as did yards per passing attempt (-0.193).
The only possible on-field explanation I can think of is that maybe Johnson was more willing to throw the ball when games were close or his team was ahead. Again though, Vandy's passing game has largely been awful outside the Cutler era, and even then, Vanderbilt's third- and fourth-highest rushing totals were in Cutler's junior and senior years when the team went 4-8 and 5-7, respectively. With yards per carry and yards per pass attempt having negative correlations with winning, it's a very puzzling situation to ponder. Toss in the negative correlation for net punting, and you've got a full-fledged conundrum.
In any event, defense and turnovers were strongly correlated with Vanderbilt's winning in the era immediately preceding Franklin's term. It will be interesting to see if things change much under the offensive-minded Franklin.