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Oklahoma Football: Digging into the Sooners’ interception issues

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What can Alex Grinch do to fix OU’s struggles with picking off passes?

NCAA Football: Army at Oklahoma Mark D. Smith-USA TODAY Sports

Among a myriad of problems with their defense in 2018, the Oklahoma Sooners played like they had a turnover allergy.

OU ended the year with a pathetic total of 11 defensive takeaways, which ranked 121st nationally out of 130 teams. Since OU played 14 games, it had the third-worst rate of turnovers forced per game in the country at 0.79, just ahead of Baylor (0.77) and Oregon State (0.67). Considering that OU’s D faced roughly 12 more plays per game than the Bears and Beavers, the Sooners really might have been the worst team in the country at forcing turnovers.

Alex Grinch, on the other hand, comes off like a turnover addict. Supposedly, OU’s new defensive coordinator is making creating more of them a priority for the Sooners this fall.

Sounds like a good idea. Yet, if you really want a great look at the myths that surround turnovers in college football, David Hale did a fantastic deep dive on the subject for last year. Similarly, Bill Connelly has written extensively about turnover luck.

Evidence suggests that most of what coaches teach about creating turnovers is as effective as asking a witch doctor to put a curse on the other team. So what does that mean for the Sooners this year?

I’m going to try to offer some analysis on the theme of turnovers in a series of articles in the coming weeks (Try to contain your excitement!) We’ll start with what would seem to be a clear culprit for OU’s recent turnover suckage: the secondary.

The ability of OU’s defensive backs – and by extension, OU’s defense as a whole – to pick off passes has tailed off considerably in the last three years.

In 2015, OU grabbed 20 interceptions. That total included 17 from defensive backs Zack Sanchez, Jordan Thomas, Ahmad Thomas and Dakota Austin.

The DBs produced 16 picks in the following three seasons combined. During that span, the number of turnovers gained by the Sooners cratered, culminating in last season’s dismal total.

According to Connelly, on average, teams can expect to convert about 22% of “passes defensed” (his term for the sum of interceptions and pass break-ups) into INTs. For its part OU had one of the worst INT conversion rates in the country in 2018, picking off six out of 63 passes defensed. That works out to a rate of roughly 9.5%, which would rank 127th nationally out of 130 teams.

If the Sooners simply hit Connelly’s average INTs-to-PDs rate of 22%, they would have snagged 14 picks.

This raises an interesting question, though: Did the Sooners just have a run of bad luck – or even natural regression – when it came to interceptions last year?

Connelly points out that the 22% benchmark applies over time. As such, a season in which a team converts a low percentage of passes defensed into picks tends to get balanced out in the long run by one with a high conversion rate. For example, the Sooners intercepted 20 of 61 passes defensed in 2015, which works out to an abnormally high conversion rate of 33%.

Looking back at OU’s INT conversion rate in the last 10 years, you see some notable fluctuations. In the aggregate, however, the Sooners produced 136 INTs on 655 passes defensed. That equates to a conversion rate of 21%; consequently, it seems tough to make a compelling case that recent trends are severely out of step with longer-term performance.

Of course, after watching opponents repeatedly torch OU’s pass defense last year, the regression argument doesn’t feel right. OU’s defensive backs struggled so badly in the other phases of their play that it just makes sense that those deficiencies would extend to picking off passes.

Intuitions aside, though, the bottom line is that there should be plenty of low-hanging fruit for the Sooners to harvest in the area of interceptions – whether they come through the cosmic mathematical scales balancing out or teaching better technique to the DBs.