The last four years of Northwestern basketball have been the best four years in the program's modern history. They've also been miserable, depressing, and full of heartbreaking losses that have led to berths in the NIT. Many theories for improving the program have been thrown around, with firing head coach Bill Carmody being the most popular. But Carmody is back for at least another season, so let's instead analyze those NIT Northwestern teams and see what needs to improve.
A quick look at Northwestern's national ranking in offensive and defensive efficiency on KenPom.com shows where the problem lies:
Northwestern since 2009
| Year | Offense | Defense |
| 2009 | 49 | 106 |
| 2010 | 33 | 169 |
| 2011 | 18 | 121 |
| 2012 | 20 | 184 |
I'm not exactly breaking new ground by pointing out that Northwestern's offense has been far superior to its defense, this has been a well-established fact for years. So instead let's look at where Northwestern ranks nationally over this time span and how they compare to their Big Ten peers.
My methodology for all the data that follows is pretty simple: I averaged the offensive and defensive efficiency of every Division I team over the last four years. The raw numbers indicate how many points the team would score per 100 possessions against an average Division I opponent. Here's the top 20 nationally in offensive efficiency:
Average Adjusted Offensive Efficiency
| School | Offensive Efficiency |
| 1. Duke | 119.36 |
| 2. Ohio State | 118.63 |
| 3. Kansas | 117.22 |
| 4. Missouri | 116.72 |
| 5. Pittsburgh | 116.51 |
| 6. Wisconsin | 116.48 |
| 7. Notre Dame | 116.27 |
| 8. Kentucky | 116.14 |
| 9. Florida | 116.06 |
| 10. Syracuse | 115.02 |
| 11. Baylor | 114.88 |
| 12. North Carolina | 114.45 |
| 13. Marquette | 114.25 |
| 14. California | 113.97 |
| 15. Vanderbilt | 113.33 |
| 16. Texas | 113.25 |
| 17. Michigan State | 113.07 |
| 18. Northwestern | 113.04 |
| 19. Gonzaga | 112.98 |
| 20. Brigham Young | 112.95 |
That's quite a list to be a part of; it's essentially a list of college basketball blue bloods with some strong up and coming programs thrown in. Bill Carmody has done an excellent job in making Northwestern's offense so effective. The other nineteen programs on that list have all made at least two NCAA tournament appearances in the past four years, and all but Baylor have made at least three.
Yet Northwestern doesn't have any. And the reason is obvious, poor defense. Here's a list of Northwestern's defensive peers.
Average Adjusted Defensive Efficiency
| 127. Weber State | 99.72 |
| 128. Buffalo | 99.73 |
| 129. Southern Miss. | 99.86 |
| 130. South Florida | 99.91 |
| 131. Nevada | 99.97 |
| 132. Texas Tech | 100.00 |
| 133. Oregon | 100.02 |
| 134. Central Florida | 100.06 |
| 135. Mount St. Mary's | 100.16 |
| 136. George Washington | 100.17 |
| 137. Northwestern | 100.21 |
| 138. Hofstra | 100.22 |
| 139. Rhode Island | 100.24 |
| 140. Louisiana Tech | 100.26 |
| 141. Boise State | 100.37 |
| 142. Charlotte | 100.38 |
| 143. Utah | 100.40 |
| 144. Boston College | 100.42 |
| 145. La Salle | 100.44 |
| 146. Marshall | 100.47 |
Yeah, not exactly the same sort of company. The vast majority of these schools haven't made the NCAA tournament once in the last four years. As much credit as Carmody deserves for the offense, he deserves an equal amount of blame for the poor defense.
So how unusual is it for a school to have this large a gap between offensive and defensive efficiency? Here are the national leaders for schools in top conference (the big six plus the Atlantic 10, Missouri Valley, Conference USA, Mountain West and West Coast).
Largest Difference Between Offensive and Defensive Efficiency
| School | Average O | Average D | Difference |
| USC | 239th | 26th | 213 |
| Providence | 36th | 187th | 151 |
| Georgia Tech | 168th | 29th | 139 |
| East Carolina | 120th | 257th | 137 |
| LSU | 189th | 63rd | 126 |
| Northwestern | 18th | 137th | 119 |
| Creighton | 31st | 149th | 118 |
| Tulane | 212th | 103rd | 109 |
| Stanford | 142nd | 35th | 107 |
| Wyoming | 183rd | 76th | 107 |
| Houston | 87th | 184th | 97 |
| Florida State | 94th | 1st | 93 |
So while Northwestern's large gap isn't unheard of, most of the rest of these teams aren't very good. Of course, in order to have a gap of at least 100, you have to be bad on at least one side of the ball, so there aren't going to be many good teams here. Only Florida State has managed to be consistently good in the past four years and that's because they've had the nation's best defense. Also, note old friend Kevin O'Neill leading his USC team to great defense combined with horrific offense.
There are a number of factors leading to the stark difference between Northwestern's offensive and defensive success. Most notably, Bill Carmody clearly puts more of an emphasis on recruiting players that fit his offensive system, namely, players that can shoot from the perimeter. Since players who are both excellent shooters and great athletes tend to be recruited by the nation's top programs, Northwestern ends up with players who are above average at shooting but below average athletically, and such players struggle to stay in front of more athletic opponents on defense and also struggle to get the rebound when the opponent misses a shot. Also, Carmody hasn't managed to recruit a big man who has provided anything remotely resembling an inside presence defensively. Adding one of those to the roster would help considerably. And it's also clear that Carmody is much better at coaching offense than he is at coaching defense.
Here's how Northwestern stacks up against the rest of the Big Ten over the past four years in both offensive and defensive efficiency.
Big Ten Offensive Efficiency
| Ohio State | 118.63 |
| Wisconsin | 116.48 |
| Michigan State | 113.07 |
| Northwestern | 113.04 |
| Purdue | 112.68 |
| Michigan | 110.97 |
| Minnesota | 109.16 |
| Penn State | 108.29 |
| Illinois | 107.68 |
| Indiana | 106.81 |
| Iowa | 105.74 |
| Nebraska | 103.37 |
Big Ten Defensive Efficiency
| Michigan State | 89.48 |
| Ohio State | 89.71 |
| Purdue | 89.85 |
| Illinois | 90.90 |
| Minnesota | 93.28 |
| Wisconsin | 93.32 |
| Michigan | 94.04 |
| Nebraska | 94.63 |
| Penn State | 97.12 |
| Iowa | 99.11 |
| Indiana | 99.29 |
| Northwestern | 100.21 |
More of the same: the offense is solidly in the upper half of the conference while the defense is dead last. The good news is that Northwestern adds a lot of large newcomers next season, most of whom should help improve the defense and rebounding. The bad news is that John Shurna, the best offensive player in school history, won't be on the roster anymore, so the offense will almost certainly get worse. And unless the defense gets quite a bit better, Northwestern will likely be headed back to the NIT, at best.