Generally speaking, I'm not a fan of picking and choosing either. There are two reasons why I do in this case. 1 - Wisconsin is more the anomaly than Nebraska. We didn't play them in 2013 and don't play anyone like 2014 Wisconsin this year. They were the #4 rushing offense in the country last year. The best rushing offense we've faced this year is #43 Northwestern. That's a pretty significant drop-off. 2 - Wisconsin had us figured out like no one else. They knew how to formation and motion into bad alignments and take advantage of that. That's still on us for lettting that happen but it also skews the big picture.I don't really disagree with you other than the significance. I'm not a big fan of picking and choosing which games to include and which not too in a statistical analysis, even if they are a bit of anomaly. I think it's interesting and another perspective, but, I don't think it's fair to draw many conclusions from. It's only one way to look at the puzzle.
Our rushing defenses for the last five years (from 2010 to 2014) have given up, on average, 155.6 YPG, 166.7, 204.9, 150.2 and 177.8. There isn't a ton of consistency there year to year, and clearly tells a different story than if you just focus on 3.8 YPC.
I'll settle on waiting to see how we finish this year before I stamp my opinion in stone. However, fact is we're on pace this year to have our best rushing defense in at least 5 years.
The reason I think it's more instructive to look at YPC is it gives a more accurate picture when you're not playing the same type of offenses. So far this year we've played the #98, #81, #116, #47, #99, #89, #103, #43, #110 and #90 rushing offenses in terms of yards per game. That's an average of #97 in the country. Last year we played #62, #46, #50, #114, #4, #30, #103, #73, #21, #65 and #63 rush offenses - averaging #57. We could be playing terrible rush defense this year and still be giving up fewer yards per game than last year simply because teams aren't running as much and aren't as good at running the ball.
We may have our best rush defense in the last five years but we have our worst pass defense ever. That also is due - at least in part - to the other side of the coin I just presented. If you look at total yards per game, we are giving up almost 60 more than last year - probably against worse overall offenses though I didn't take the time to look at that. You have to go back to 2007 to find a defense worse than this and that team at least played several teams with legitimate offensive weapons.