BYU fans seem to hate Tuiaki's defense. But does the data back up their hatred? So here's what I did: I looked at the yearly rankings for Tuiaki's defense at BYU and compared it to how BYU's D has traditionally done in those same statistical categories. 

Some notes:

- Rankings - I believe looking at the defensive rankings each year is the most accurate way to do it, because looking at the raw numbers is too variable. College football is very different today than it was in 2006, 2012 or even 2016 when Tuiaki took over, so the best way to compare is to see where BYU's D ranked in a host of categories in those years. I realized that looking at BYU's rankings in several defensive stats is perhaps the best way to gauge success or failure.

- Noise - Obviously there's statistical noise when you look at anything. For instance, BYU's 2012 team had probably the best D ever. But our offense was below average. Had BYU been able to even field an average offense, BYU's D could, perhaps, have even been better. This is also true of the 2017 team when BYU had the 2nd worst offense in all of college football. Point is this: there are always a ton of factors that influence defensive football.

There were also stretches during Bronco's era where he didn't call defensive plays. AND stretches during Tuiaki's era where Kalani has been more involved than others. The point is simply to look at the Defenses Tuiaki has overseen and compare them to another era in BYU history and see how he compares.

- Schedule - If you go back year by year (which I did), Bronco--top to bottom--played an EASIER schedule than Tuiaki's defenses have. Bronco had the end of the MWC era and then early days Independence which included mostly WAC teams for several years. Tuiaki's defenses have played more P5s than Bronco almost every year--which the exception of 2020.

- Factors ranked - I looked at BYU's ranking in the following statistical categories: Offensive TOP Allowed, Takeaways, Yards Allowed per Game, First Downs Allowed Per Game, Scoring Defense.

The Analysis

Takeaways - One of criticisms of Tuiaki's D is that he doesn't pressure enough which therefore doesn't produce turnovers. It's also a good measure of athleticism and risk-taking on D.

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• Bronco (05-15) - BYU's defenses ranked 47th in the nation for takeaways on average during this time at BYU. 
  
• Tuiaki (16-21) - Ranked 53rd on average for takeaways.
  
• Conclusion - Tuiaki's defenses do WORSE than the previous regime did at generating turnovers relative to the rest of the country in those specific seasons. 
  

Offensive TOP Allowed per Game - One of the primary criticisms of Tuiaki's D is that he allows long, demoralizing, discouraging drives. But is this true?

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• Bronco (05-15) - BYU's defenses during this period ranked 50th in the nation in terms of offensive TOP allowed. 
  
• Tuiaki (16-21) - BYU's defenses during this period rank 65th in the nation in terms of offensive TOP allowed. 
  
• Conclusion - Tuaki's defenses do WORSE than the previous regime in terms of offensive TOP allowed. In short: Tuiaki's D allows longer drives and more of them. 
  

First Downs Allowed per Game - One of the criticisms of Tuiaki's D is that it allows LOTs of First Downs. 

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• Bronco (05-15) - BYU's defenses during this period ranked 47th in the nation in terms of First Downs allowed
  
• Tuiaki (16-21) - BYU's defenses during this period ranked 50th in the nation in terms of First Downs allowed. 
  
• Conclusion - Tuiaki's defenses do SLIGHTLY WORSE than the previous BYU defenses in terms of First Downs allowed. 
  

Yards Allowed per Game- Do Tuiaki's defenses really allow more yards per game? 

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• Bronco (05-15) - BYU's defenses during this time ranked on averaged 38th in the nation in yards allowed
  
• Tuiaki (16-21) - BYU's defenses during this time ranked on average 40th in the nation in yards allowed. 
  
• Conclusion - Tuiaki's defenses do SLIGHTLY WORSE than the previous BYU defenses in terms of First Downs allowed. 
  

Points Per Game - The most important metric. The metric that all the previous metrics drive to.

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• Bronco (05-15) - BYU's defenses during this time ranked 33rd in scoring defense on average. 
  
• Tuiaki (16-21) - BYU's defenses during this time ranked 30th in the scoring defense on average
  
• Conclusion - Tuiaki's defenses do SLIGHTLY BETTER than the previous BYU defenses in terms of scoring. 
  

Conclusions and Thoughts

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• Both Tuiaki apologists and haters will find something they like in this data. 
  
• This isn't about comparing Tuiaki to Bronco per se, but I just needed another BYU cohort to compare Tuiaki to. Seemed like the previous regime was the best way to do it. 
  
• Tuiaki is correct in his bend but don't break philosophy, if you care about limiting points. While he does worse in EVERY OTHER defensive category, he did better than the previous regime in terms of allowing points. Said another way: in the only statistic that actually matters, he does better. 
  
• 2012 and 2017 made my ill when I dug into the data. 2012 we ended the season with the 3rd best defense in the country. But our offense was bad. 2017 we ended up with a slightly below average defense but the WORST offense in America by some measures and 2nd or 3rd worst by others. We simply couldn't score. 
  

Again, I contend that the best way to judge Tuiaki is to look at where his defenses rank in a given year for various categories and then compare that to BYU historically. That's the whole idea of what I was trying to do. 

It's also sobering to realize that generally speaking--we're between the 30th and 60th best defense in the country, which means we're actually outperforming our recruiting classes as a general rule. When looked at it through that lense, our defenses have actually performed very well for the last 15 years. There is likely NO DEFENSIVE COORDINATOR who could allow BYU to perform dramatically better on defense unless they were also a far far better recruiter.