Iowa's Defense 2003-2010 (The Rest of the Leftovers)

If you've read the the accompanying posts, you know how this goes. Since I'm snowed in today, I have time for more analysis than I did in the offensive one.

First, defensive points allowed per game:

The 2006 version of Iowa's defense was the only team to ever give up more (just slightly) than Big 10 average points per game. If you're looking up points per game and these don't match, it's because I took out points given up on kick returns or any other plays that the defense was not on the field. 2003, 2008, and 2009 were really stingy on points. 2010 was really good at this through the first eight games, the last four games raised their average to about 16.

• Iowa's eight year average: 16.17 defensive points per game allowed
• Big 10 eight year average: 21.94 defensive points per game allowed

Next, yards per play allowed:

Iowa has had one season in the last eight years where they have allowed over 5 yards per play. Even in that year, they were still better than Big 10 average. 2009 they only gave up 4.26 yards per play. That's pretty insane.

• Iowa's eight year average: 4.62 yards per play allowed
• Big 10 eight year average: 5.20 yards per play allowed

Yards per pass attempt:

The pass coverage hasn't been quite as dominant over the years. Although, it has been above average. The 2008 and 2009 teams were quite good at stopping the pass. 2010 took a bit of a step back. But, with Iowa's defense, you take away the points and deal with the yards.

• Iowa's eight year average: 6.10 yards per pass attempt allowed
• Big 10 eight year average: 6.73 yards per pass attempt allowed

Opponent quarterback rating:

In 2005, Iowa did allow opposing quarterbacks to put up an above average quarterback rating against them. In 2006 and 2007 they came close to repeating that. 2008 and 2009 were a different story. 2008's defense held opposing quarterbacks to a 98.31 rating. The odds of that happening again aren't great right? Wrong. 2009 caused many opposing quarterbacks to see the bench. Allowing only  a quarterback rating of 90 (!).

• Iowa's eight year average: 110.67 quarterback rating
• Big 10 eight year average: 122.27 quarterback rating

Pass attempts per touchdown allowed:

2006 was the low point in giving up passing touchdowns on defense. They gave up a passing touchdown every 21.15 pass attempts. Big 10 average that year was 22.52 pass attempts. 2008 only allowed a touchdown every 51.44 pass attempts. 2009 wasn't too shabby, with one every 42.56 pass attempts. The Big 10 this year was really down in pass defense apparently. Opponent quarterback rating, yards per pass attempt, and pass attempts per touchdown were all at their eight year high. Was it a result of especially good quarterbacks or especially bad pass defenses?

• Iowa's eight year average: 35.35 pass attempts per touchdown
• Big 10 eight year average: 23.50 pass attempts per touchdown

Pass attempts per interception:

For the most part, Iowa has been good at picking off opposing quarterbacks. 2005 was the only they were not. 2008 and 2009 further solidify the idea that they were the best passing defenses in the last eight years. Overall, Iowa has actually picked off opposing quarterbacks in about 7 fewer passes than they have allowed a touchdown pass. A good thing.

• Iowa's eight year average: 28.65 pass attempts per interception
• Big 10 eight year average: 32.29 pass attempts per interception

Now, on to rushing. Yards per carry allowed:

Iowa is good at stopping the run. 2006 was the worst year according to yards per carry, allowing 3.62 yards per carry. That is the most any Iowa defense has given up in the last eight years. Not to mention, they've held opponents to under 3 yards per carry twice. Iowa's defense is definitely stingy when it comes to yards on the ground. Oddly enough, 2010 was also the worst year for the Big 10 in yards per carry allowed too. Were defenses down this year?

• Iowa's eight year average: 3.15 yards per carry allowed
• Big 10 eight year average: 3.85 yards per carry allowed

Carries per rushing touchdown allowed:

As with any defensive scoring category, Iowa is good. 2006 was a bad year, allowing a rushing touchdown every on 34 touches by a running back. The 2009 defense only allowed a rushing touchdown every 89.28 carries. This year, the defense came back to earth and gave up a rushing touchdown every 31.31 carries, beating 2006's low mark.

• Iowa's eight year average: 49.61 carries per rushing touchdown allowed
• Big 10 eight year average: 28.47 carries per rushing touchdown allowed

Plays per touchdown allowed:

The 2006 was once again very close to being worse than Big 10 average. The 2008 defense made opposing offenses go 53.75 plays before letting them into the endzone. Considering that most teams average about 60 to 70 plays a game, that is almost the whole game before Iowa would let a team into the endzone. 2008 was very similar, allowing a touchdown every 46.89 plays. 2010's team was still way above average, but fell off by about 11 plays from 2009's defense.

• Iowa's eight year average: 39.04 plays per touchdown allowed
• Big 10 eight year average: 25.83 plays per touchdown allowed

Finally, plays per turnover forced:

Iowa hit a bit of a rough patch from 2005-2007, where the defense was forcing turnovers at worse than league average. 2008 and 2009 they bounced back. But, 2010 Iowa only beat the Big 10 average by 2 plays. 2004 was the best year, forcing a turnover every 25.5 plays or almost two and a half times per game.

• Iowa's eight year average: 37.42 plays per turnover forced
• Big 10 eight year average: 38.98 plays per turnover forced

To wrap this up, Iowa's defense was better and more consistent than its offense over the last eight years. Unlike the offense, the defense was above average in every one of the stats above. If you go back to my first post, Iowa averaged 46% better than the Big 10 average in rushing defense and 28% better in scoring defense. Those are clearly their biggest strengths. However,  they also averaged out to 11% better in yards allowed, 10% better in passing defense, and 4% better in causing turnovers. So, when you get frustrated that an opponent is "dinking and dunking" its way down the field, remember that Iowa is 28% more likely than the average Big 10 team to keep them off the board and 4% more likely to cause a turnover.