How Do Basketball Teams with Great Offenses and Not So Great Defenses Fare Both in the Big Ten and Nationally?

By houksyndrome on July 31, 2020 at 12:15 pm
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© Jeffrey Becker-USA TODAY Sports

Hi folks!  I’m back with some basketball statistical analysis to distract us from the scandal in which the football program currently finds itself.  I know it’s a weird time of year for an article like this but, hey, 2020 is a weird year and it just so happens that a crucial event for the Iowa Men’s Basketball program will be occurring in the coming days:  Luka Garza’s decision about whether to return for his senior season.  If he leaves, all of my projections about the coming season go out the window.  Hence my decision to analyze this stuff now, since there might be nothing to analyze (and write about) a few days from now.  Enjoy the dream while we still can, I say!

Based on the statistical performance of the team over the last couple of seasons, I think I have pretty reasonable idea of the type of team that we will have this year:  really good on offense with major question marks on defense.  Last year, Iowa had the 5th best offense in the country and the 97th best defense in the country, per the Pomeroy ratings.  If Luka comes back for another season, Iowa will have its top four offensive players returning + Bohannon at full health for the first time in years.  Based on that, I am very confident projecting this as a top 10 offense next season.  Even that might be overly conservative.

Iowa had the 5th best offense last year in spite of the fact that they really only had a couple of good outside shooters in their rotation.  Next season, Bohannon will give Iowa another flamethrower from outside plus there will be several new arrivals who might also be able to knock down threes.  Any lineup with Garza inside and Fredrick + Wieskamp + Bohannon outside is going to be extremely potent offensively.  So, for the sake of analysis, let’s assume a top 10 offense and look at how such teams have fared, both in the Big Ten and at the national level, during the period when Ken Pomeroy has kept efficiency statistics (2001-02 season to present).  My goal is to look at how teams with statistical profiles like Iowa's compare with teams that win Big Ten championships and make deep runs at the NCAA tournament.

Let’s start by looking at the offensive and defensive efficiency rankings (at the national level) of every Big Ten champion from 2001-2002 to present.  During this time, 29 teams have won a share of the Big Ten regular season championship.  Here are the offensive and defensive rankings of those teams:

The offensive and defensive rankings of all Big Ten Champions (2002-Present)

Only one team, Michigan in 2013-14, has managed to win the Big Ten without a top 65 defense.  That 2013-14 Michigan team had the 3rd best offense in the country and the 89th best defense.  So the idea of winning a Big Ten championship with a great offense and mediocre defense has precedent.  It is, however, very rare and Iowa's chances of having a really special season would be much, MUCH higher if the defense could get into, say, the top 60.  On the bright side, winning a Big Ten championship with a mediocre offense is even more rare.  The worst offensive team to do so was 2009-2010 Purdue (#64 on offense, #4 on defense).  They were one of two teams to win a Big Ten championship during the Ken Pomeroy era without a top 40 offense.  The only other team to do so was Wisconsin in the 2001-2002 season.  (Not) fun fact: the 2001-2002 Wisconsin Badgers won a share of the Big Ten Championship with the 53rd best offense and 61st best defense in the country (by far the worst team to do so during the last two decades).  Overall, they were the 50th best team in the country that season per Pomeroy, and they won a share of the Big Ten title.  Typical Wisconsin bullshit.

Part of the reason why there has only been one team to win the Big Ten with a great offense and mediocre defense is that such teams are quite rare, both in the Big Ten and nationally -- offense and defense tend to correlate with one another.  During the past two decades, only eight teams have had a top 10 offense and a defense that was outside of the top 60.  They are shown in the table below.  As you can see, aside from the Michigan team that won the league, none of these teams managed to finish better than 5th in the conference.

Big Ten teams with top-10 offenses and sub-top-60 defenses
Team Offensive Rank Defensive Rank Overall Rank Finish
2006 MSU 10 119 27 6
2012 Purdue 10 114 30 6
2015 Indiana 8 200 48 7
2020 Iowa 5 97 23 6
2012 Indiana 4 72 9 5
2014 Michigan 3 89 12 1
2014 Iowa 5 77 22 6
2017 Michigan 4 69 20 5

The situation seems to improve dramatically once you get into the top 60, defensively.  From that figure above, you can see that seven teams have won at least a share of the Big Ten championship with defenses in the 30-61 range.  Moreover, the table below depicts all of the Big Ten teams to have a top 10 offense and a defensive ranking between 30th and 60th.  There are eight such teams and half of them won league championships with the worst league finish being fourth place, by Michigan in 2012-2013 (and that team was National Runner-Up!).  So, if Iowa can just get that defense into the top 60, they should have a legit shot at doing something that Iowa hasn’t done during my lifetime:  win a Big Ten Regular Season Championship.

Big Ten teams with top-10 offenses and 30-59 defenses
Team Offensive Rank Defensive Rank Overall Rank Finish
2004 Illinois 8 39 13 1
2011 Wisconsin 2 52 6 3
2013 Michigan 1 37 4 4
2014 Wisconsin 4 35 5 2
2015 Wisconsin 1 35 2 1
2016 Indiana 6 59 11 1
2018 Purdue 2 31 5 2
2019 Purdue 4 34 9 1

Just to dream a bit, and because I already compiled the data, here is how teams with top 10 offenses and top 30 defenses have fared in the Big Ten:

Big Ten teams with top-10 offenses and top-29 defenses
Team Offensive Rank Defensive Rank Overall Rank Finish
2005 Illinois 3 4 2 1
2005 Michigan State 6 28 5 2
2007 Ohio State 4 11 3 1
2010 Ohio State 8 26 7 1
2011 Ohio State 1 12 1 1
2012 Ohio State 6 4 2 1
2013 Indiana 2 19 3 1
2016 Michigan State 2 26 5 2
2019 Michigan State 5 9 3 1

That’s right: seven of the nine teams have won the conference.  While top 30 defenses have happened a few times in the McCaffery era, it has not happened since Gesell, Clemmons, Woodbury and Uthoff graduated, so it seems very unlikely that this personnel group will be able to pull that off.  If they do, however, Iowa would likely win the Big Ten and be a major factor in the National Title race as well.

Now let’s talk a bit about how teams like this have tended to do at the NCAA Tournament over years.

NCAA Performance for teams with top-10 offenses
Defense Range Total teams Sweet 16 Elite Eight Final Four Runner Up Champions
91+ 39 11 3 1 0 0
60-90 24 10 2 0 0 0
30-59 44 27 15 6 2 0
1-29 73 62 49 30 4 15

As was the case for the Big Ten, it is rare to have an elite offense paired with a lousy defense when examining the entire NCAA.  During the last 18 seasons (not counting 2019-20, since there was no NCAA Tournament), there have been a total of 39 teams with a top 10 offense and a defense outside of the top 90.  Of these, 11 made the Sweet 16 or better, three made the Elite Eight or better, and one made the Final Four.  That lone Final Four participant was the 2002-03 Marquette team featuring Dwyane Wade (2nd on offense, 109th on defense). 

Similarly, only 24 teams have finished with a top 10 offense and a defense in the 60-90 range.  Ten of those teams made the Sweet 16, two made the Elite Eight, and none made the Final Four.  So if you have an elite offense but a mediocre defense (i.e. 60th or worse), you’ve got about a 33% chance of making it to the Sweet Sixteen.

In contrast, if you manage to get that defense up into the top 60, things get much better.  For teams with top 10 offenses and defenses between 30 and 59, there are 44 total teams, 27 of whom made the Sweet 16, 15 of those made the Elite Eight, six of those made the Final Four, and two of those made the championship game (none have won).  So combining a top 10 offense with a good-but-not-great defense has about a 60% shot at the Sweet 16 and a one in three shot at the Elite Eight.  Sign me up for that! 

Things are even rosier if you combine a top 10 offense with a top 30 defense.  There have been 73 such teams and 62 of them have made the Sweet 16 (!), 49 made the Elite Eight (!!) and 30 made the Final Four (!!!).  In fact, 15 of the 18 champions during the Pomeroy Era had a top 10 offense paired with a top 30 defense.  Obviously, this personnel group pulling off a top 30 defensive performance is probably a pipe dream; however, I think top 60 is achievable for this group of players and that would carry with it a 60% chance of reaching the Sweet 16 and a 50% chance of winning the Big Ten, based on historical comparisons.  I’ll take those odds.

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