Are Big 10 Defensive Stats Inflated by Bad Offenses? A P5 Conference Comparison

There is an interesting dichotomy of the views of Michigan's defense of 2014 - some view it as a "top 10 defense" because the NCAA stats say so.  Others (hand raised) use more of an eye test and advanced stats, specifically FEI and S&P+ via Football Outsiders, which have various measures to adjust for SOS, garbage time points, etc.   (more info on how those stats are derived can be found on that site - I wont rehash)

Let's take a closer look at the NCAA stat for total defense which sports journalists of both the print and video variety tend to parrot.  What does it really track?  Only 1 thing:  total yards given up per game.  It is very simplistic and in my estimation misleading.  My thesis has been this gives an overinflated value to all Big 10 defenses because Big 10 offenses have really stunk it up of late, especially the past half decade.   So this piece will try to fact check my opinion.

There have been very few premium QBs the past 6-7 years in the Big 10 until last year... the last golden batch was 2007-2008 when you had Henne, Smith, Stanton.  Before that you had to go to 2004 to Navarre, Sorgi, Krenzel, Smoker.  1 year of Russell Wilson and Kirk Cousins really are all you have had up to about 2013 and after 2008.  It's been 18 years since the Big 10 had a QB drafted in the 1st round although there is finally the potential for 3 at once in 2016 with Cook, Hackenberg, and Jones.  But even Hackenberg was a disaster last year.  So you get the general point - when you look at passing stats of Big 10 offenses vs those of the Pac 12, SEC, Big 12 - it has lacked severely for most teams... Wisconsin was throwing out a converted safety last year as a QB and they were the 3rd best team in the conf.  Gary Nova - in the conference for all of 1 year, was the 3rd best QB (If you group all the OSU QBs as one since only one plays at a time) in the conf last year.   Kevin Hogan in the Pac 12 ?  A lower third QB ... in the Big 10?  Awesome throw god....

I don't recall what week it was (maybe week 8 or 9) 8 of the top 25 defenses in the country per the NCAA stat were in the Big 10.  Even in the year end results the Big 10 had 4 of the country's top 10 defenses (PSU, Wisconsin, UM, MSU)... and 6 of the top 22 (OSU, Iowa)  Wow what a performance! Elite defenses all over this conference!! 

Or is this really a confluence of mediocre to poor offenses with some former powers looking awful (PSU, UM) and other recently high octane offenses (Indiana) hampered by a true freshman QB, while others were run by a former safety for much of the year.   Advanced stats say the latter - in fact only 2 offenses made the top 30 in the country via FEI; OSU and MSU.  Some Big 10 teams in the West avoided both those offenses, and others only played 1.  So you could in theory go through your conf slate playing 0 or 1 of the top 30 offenses in the country.  Wisconsin's 1 dimensional offense was 33, and then you have to drop to 50 to find another Big 10 team.  It's was an awful year save for a few teams on that side of the ball.  And advanced stats say only Wisconsin and PSU had anywhere near elite defenses - and you saw what OSU did to Wisconsin.

So with run heavy schemes without Jeff George, Chuck Long, Drew Brees (hell Kyle Orton) types populating mid level teams in the league (and of course those schools wont have that type of QB every year), Big 10 defenses have feasted.  Or at least that is my opinion so I thought I'd use advanced stats to compare the major conferences.

Below is a comparison chart of 7 teams comparing FEI offensive stats of their conference only schedule in 2014.  The lower the average rank, the better the average offense faced.  I've created a pool of 2 Big 10 teams (one from the East, one from the West), 2 SEC teams (one from the much tougher West, one from the East), and then 1 team from the other 3 power 5 conferences.  I chose mid level type teams (excl Michigan which had 5 wins) of 7-9 wins on average to try to compare similar teams from each conference in 2014.  Not the top teams, not the bottom teams....

This led me to: Nebraska, LSU, Tennessee, Louisville, West Virginia, Utah -along with control group Michigan.

My theories going into this were:

1. The Pac 12 features the most NFL arms and prolific offenses so their defenses would be most stressed and thus a high defense ranking in that conf actually means something.
2. The Big 10 and ACC would both suffer from a lot of mediocre offenses and thus their defenses (per NCAA stats) would be overinflated.
3. The Big 12 rank in terms of opponent offensive rank would be closer to the Pac 12 although the struggles of Texas would hurt.
4. The SEC West would rank very well, somewhere near the Big 12 while the SEC East would be hurt by the brutal (Michigan/PSU like) Florida offense

These are obviously 1 year data points specific to any 1 team (or 2 teams) in a conference (picking another team would give some variability) but I do think by and large they would hold up over the past half decade to give us a general trend (Obviously the Big 12 has changed body count over that time frame as has the Big 10 and SEC).

The Rankings Unadjusted

Let's see what the data told us (the # to the right of each team is their offensive FEI rank - lower = stronger)  UM was 82 for comparison.

What does this data set say?

• As predicted in theory 1, Utah had the most onerous schedule.  Pac 12 offenses are very good - they only faced ONE offense with a rank outside the FEI top 48.  Again there are only 3 teams in the entire Big 10 with a ranking inside the top 48. Week in and week out - its brutal and the 32.0 ranking clears the field.  (of course a cynic could say Pac 12 defenses are bad and Pac 12 offenses feast on bad defenses but I'd say the eye test disagrees - the Pac 12 offenses put a ton of pressure on you with a lot of pass oriented spread teams).
• As predicted in theory 2, Big 10 defenses had a huge advantage as the 57.9 opponent rank for UM and 56.6 for Nebraska were far and away the worst readings out of all 7 teams.   And for all the talk of the how weak the Big 10 West is, the Big 10 East had even worse offensive outputs via FEI.  But its very close - any defense in the conference had a much easier time than in any other conference.
• I was wrong in theory 2 about the ACC, I thought their offenses were as bad as the Big 10s.  In fact they were right on par (with Louisville's 49.0) to the SEC East, and the Big 12.
• I was wrong about theory 3, than the Big 12 would be closer to the Pac 12 then not.  The offenses in that conf were not dissimilar to the ACC, and SEC East.  But part of that is due to both Oklahoma State and Texas having really bad offenses so it's a bit of an outlier this year.  More on that later.
• I was correct on theory 4, the SEC West had the 2nd best offensive output - thus difficult on their defenses, and the SEC East was pushed down to average due to Florida.  In fact every SEC West opponent for LSU was in the top 50 - even better than Utah's opponents.  Surprising as we assumed this was a down year for SEC offense with a down year for SEC QB play.

The Rankings Adjusted

Now I decided to take this one step further and create an adjusted set of data.  What does the adjusted data do?  It simply takes a handful of teams above and puts them nearer to a historical reading - those teams would be UM, PSU, Clemson, Florida, Texas and Oklahoma State.  I also threw in Indiana to try to make Michigan look better :P and also to account for their offenses of late which under Wilson are usually decent...when not run by a true freshman model.  So I re-ran the numbers giving those schools a 35 FEI offensive rank.  That is not world beater but it is solid (Wisconsin like).  Let's see how the data changed.
 

What did the rerank do?  It benefited the Big 10 East (UM) and Big 12 team (WV) the most as it rocketed up PSU - Indiana - OK State - Texas.   2 teams for each schedule - and in a 8 game schedule that is (math alert!) 25% of the schedule adjusted.   Louisville benefited from Clemson, and both SEC teams from Florida.   There was no benefit to Utah.

Results?   The SEC West moved ahead of the Pac 12.  A bit surprising because it felt like a down year for SEC West offenses.  But these are clearly the 2 most competent conference / divisions from an offensive standpoint.   Coming in 3rd was the Big 12 - which more fits my theory #3 above.  So I believe my theory that the Big 12 is a good offensive league is true in general but didnt hold so much in 2014 as Texas and Oklahoma State had abnormal readings.

The Big 10 East and SEC East would be more on par with each other if PSU/Indiana (and Michigan) and Florida were more normal rather than abysmal.   Then just behind them would come the ACC if Clemson had been a more typical offensive power as they usually have been under Chad Morris.  Then way way way at the bottom is the Big West - which would support the case the Big 10 West sucks if UM and PSU can ever find their way.  But for the purpose of this exercise - even adjusting to "normal times" for PSU and UM, and a Kevin Wilson Indiana the typical Big 10 defense is going to have the easiest time out there- and hence their stats are going to be inflated via NCAA.com's stats.  Throw in their normal foray into the offensive juggernauts of the MAC in their non conf schedules and it gets even more slanted for Big 10 defenses.  As expected the ACC would not be too far behind the Big 10 in a "normalized" environment. 

The other 3 conferences are on a different plane, esp the SEC West and Pac 12 in terms of offenses and their defenses suffer.  Or put another way - if your defense is performing in those conferences / divisions they have really earned it. 

Or if you are a Big 10 apologist you can just yell they dont play no stinking defense in the SEC or Pac 12....  Or you could also blame cold weather for bad offenses and bad passing attacks but teams in Boston, Columbus, East Lansing, West Lafayette (in the Tiller years), Ann Arbor (in the Carr years), South Bend, et al seem to be able to run nice offenses even in northern climates so I dont buy the excuse.  Lack of good QBs is more the issue.

Before looking at this I felt UM disappointed on defense last year relative to expectations - despite their "top 10!!!" ranking.  Now - adjusting for what appears to be the easiest set of offenses faced in 2014 in any conference / division it makes it even more disappointing considering a relative good amount of talent and experience on that defense.  Most advanced stats only had the defense around #40ish in the country despite an array of mediocre offenses faced.  Going forward, it is worth keeping this sort of data in mind when comparing conference defensive achievement - the Big 10 (and ACC) defenses seem to have a quite clear advantage.