Testing Manny Diaz's argument that turnovers start with run defense

Manny Diaz, the new defensive coordinator at Mississippi State, led the Lousiana Tech defense to the most turnovers in the country last season, so he's obviously knows a thing or two about generating turnovers on defense.

That's why everyone paid attention when he recently said to Coaching Search,

"It's always going to start with stopping the run. If you stop the run, you make them have to throw to beat you. If they have to throw to win, the ball is in harm's way. No one turns the ball over more than the quarterback.

"There's a bunch of things you can do to get after the quarterback to make him make mistakes. But if you can't stop the run, then you have no chance of doing that. Our run defense will be the first thing we'll pride ourselves on. Anything from that point on, that's where the turnovers start to come."

That's a pretty interesting argument. Increasing turnover margin doesn't necessarily start with the guys that are going to be recording the interceptions or necessarily recovering the fumbles -- it starts with the front seven and run defense.

So I decided to test that with a little regression analysis -- is there any significant relationship between defensive rushing S&P+ and turnovers gained from last season?

There's enough evidence to reject the null hypothesis that there isn't a relationship between defensive rushing S&P+ and turnovers gained. Rush defense doesn't explain the whole variation in the data on turnovers gained (r squared is .14), but the two variables do seem to be related in a non-random way (at the 95% confidence level).

In short, the stats do seem to support Diaz's argument that a defense should work on stopping the run first and foremost for more turnovers.