Was Gene Chizik a Good Hire at DC?

The S&P+ Ratings are "a college football ratings system derived from the play-by-play data of all 800+ of a season's FBS college football games (and 140,000+ plays)", and one of its components is "Success Rate":

Success Rate: A common Football Outsiders tool used to measure efficiency by determining whether every play of a given game was successful or not. The terms of success in college football: 50 percent of necessary yardage on first down, 70 percent on second down, and 100 percent on third and fourth down.

I logged every single defensive play from UNC's season, and our overall success rate was 50.38%, well above the FBS average of 41.33% (for a defense, a lower success rate is better). As I had found previously, our defense was very bad on 3rd and 4th down:

Totals
Down	Success	Count	Success Rate
1	206	415	49.64%
2	152	313	48.56%
3	99	190	52.11%
4	12	13	92.31%
All	469	931	50.38%

My ultimate goal was to compare our defense this year with those under Gene Chizik, who was recently hired as UNC's new defensive coordinator, using the S&P+ Defensive Rating as well as others. That success rate ranked 122 out of 125, and our overall S&P+ Defensive rating ranked 113th.

The last time Chizik called defensive plays was when he was c0-defensive coordinator at Texas in 2006. I don't have the success rate data for that team, but S&P did produce ratings for that year, in which Texas ranked #27 (compared to UNC's #113 this past season). Our passing S&P+ ranked #101, and Texas ranked #56 in 2006, which is not outstanding but still an improvement. Chizik was also with Texas as co-DC in 2005 when they won it all, and Texas's defense ranked #1 that year.


The last time Chizik was the sole defensive coordinator at a school was 2004 with Auburn. S&P doesn't exist for that year, so I turned to Massey's Ratings, and Auburn ranked #2 defensively. For comparison, UNC ranked #128 this year in these ratings.

So even a #27 defense would be a huge improvement for North Carolina; thus, Chizik seems like a great hire, especially considering his name recognition. But that might signify the opposite: as Stan Hooper puts it, "It says everything about his reputation as a coach that he could be fired a year after winning the national title and no AQ would touch him for a year." His total record as a head coach was 24-38 between Iowa State and Auburn "when not gifted an NFL quarterback by his boosters." He was .500 in the SEC, with a 38-38 total record (including the Cam Newton year), and was ""Inept and easily the worst head coach to win a BCS title."

However, I'll end on a more positive note. Chizik employed a 4-3 defense at both Texas and Auburn, and presumably will at North Carolina, and the players apparently were not at all happy with the previous 4-2-5 scheme (so there will almost certainly be an improvement). Here are the final comparisons between UNC 2014 and Texas 2006:

UNC 2014
Defensive S&P+: 105th
Rushing: 86th
Passing: 102nd
Success rate: 48.2%, 120th

Texas 2006
Defensive S&P+: 27th
Rushing: 3rd
Passing: 56th