Oklahoma State forced 5 turnovers in 44-10 rout over Oklahoma in this year’s Bedlam rivalry game. The turnovers had such an impact that Oklahoma didn’t score a touchdown until late in the 4th quarter despite racking up 358 yards. Oklahoma State preaches creating turnovers in practice, as players are required to repeat plays or run afterwards if they do not force enough turnovers. Defensive coordinator Bill Young’s units have forced 42, 34 and 30 turnovers in his 3 year tenure, well above the 22 turnovers that an average bowl subdivision defense gets a year.
But can a team really force turnovers?
An analytic approach to turnovers
Bill Barnwell at Grantland has done the most complete study of forcing turnovers. After the Pittsburgh Steelers only forced 2 turnovers in their first 5 games this year, Barnwell asked whether turnovers in the first 5 games can predict turnovers in the remaining 11 games. To answer this question, he looked at all NFL teams from 1990 through 2010 and calculated the correlation coefficient between early and late season turnovers. This coefficient is related to a scatter plot in which each point represents a team’s turnovers in the first 5 games and last 11 games in its horizontal and vertical coordinate respectively. The correlation coefficient, which ranges from -1 to 1, describes the scatter of this plot. See Wikipedia for pictures corresponding to values of the coefficient. A correlation coefficient of 0 implies high scatter with no trend between the two variables.
For his NFL study, which included over 600 data points, Barnwell found a correlation coefficient of 0.14, a very weak correlation between turnovers in the first 5 games and last 11 games. To think about this a different way, the square of the correlation coefficient is a measure of how much of the variation in the turnovers the last 11 games is explained by the turnovers in the first 5 games. Only 2% of this variation is predicted by early season results. For example, after getting only 2 turnovers in their first 5 games, Pittsburgh has forced 12 turnovers in their last 10 games.
Barnwell’s study suggests that Oklahoma State’s high turnover total will not correlate with their Fiesta Bowl performance. Turnovers are not that useful in predicting future performance. While Oklahoma State’s defense is 9th in our defense rankings, which is scoring defense that accounts for strength of schedule, this might be too high because of their good fortune in turnovers.
How Oklahoma State’s defense will match up with Stanford
To better understand how Oklahoma State’s defense will match up with Stanford’s 5th ranked offense, let’s break down rushing and passing separately. According to cfbstats.com, Oklahoma State’s defense gives up 4.34 rush yards per carry, 72nd worst in the country. This softness was apparent on a cold night in Ames. In overtime, Oklahoma State needed to prevent Iowa State from scoring to force another overtime. Instead, they gave up a touchdown on 3 straight running plays. Of course, this poor defense might have been caused by an urgency to force a fumble. But this just shows that a defense can’t necessarily force a turnover when it needs it most. Stanford has a run first offense that gains 5.33 yards per play. Quarterback Andrew Luck barely threw a pass when the running game racked up 10.1 yards per carry against Washington. If Stanford can get an early lead, Oklahoma State’s defense will see a steady diet of running plays.
Through the air, Oklahoma State’s gives up 6.2 yards per pass attempt, 15th best in the nation according to cfbstats.com. They give up fewer yards per attempt than Oregon, a defensive unit that gave Stanford fits in the passing game. After that game, Bay area media would not stop talking about how Cardinal receivers couldn’t get separation from Oregon’s secondary. Life might be difficult for Andrew Luck and the Cardinal offense if they fall behind and have to throw on the majority of plays.
The most recent team rankings predict Oklahoma State by 6.6 over Stanford. We’ll see how turnovers affect the actual outcome of the game.
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