Banks defenses:
CMU (first DC job)
2007: 36.9ppg
2008: 30.2ppg
2009: 18.9ppg
Cincinnati (co-DC)
2010: 28.0ppg
2011: 20.3ppg
Illinois (co-DC)
2012: 32.1ppg
2013: 35.4ppg
2014: 34.0ppg
2015: 23.2ppg (new HC)
Penn State (co-DC)
2016: 25.4ppg
2017: 16.5ppg
2018: 20.5ppg
2019: 16.0ppg
2020: 27.7ppg
The first 3 seasons at Illinois they had a terrible HC, and the offense was atrocious under him the defense actually averaged more plays a game on field and the offense turned it over a ton. They hire a new HC and the defense improves by almost 11ppg, first year the offense spent more plays on the field than the defense too.
His time at Penn State I'm sure has benefited his knowledge as well. Seems like a good player developer based on the year to year improvement early in his career and he can recruit pretty well too.