It’s hard to sustain defensive success in college football. The teams that can do it — like Alabama and, to a lesser extent Wisconsin — enjoy huge success because they have defenses that keep them in games every single year. Other teams’ defenses rise and fall, because this sport moves in cycles. Coaches change jobs all the time, and the best players come and go every couple of years.

This is a post about teams that made massive jumps or declines on the defensive side of the ball in 2014. There are many instances of both, based on changes in Defensive S&P+ ranking from 2015 to 2016. That’s a metric that adjusts for opponent strength and crunches play-by-play data to get a sense of a defense’s true quality. Here’s this post’s counterpart, which measures the same changes on offense.

2016’s 14 biggest risers in Defensive S&P+ Team Def Rank 15 Def Rank 16 Def Change Team Def Rank 15 Def Rank 16 Def Change Central Florida 112 30 82 Indiana 110 31 79 Colorado 89 12 77 Rutgers 118 56 62 Arkansas State 91 34 57 Oregon State 104 49 55 Tulane 101 47 54 Army 120 66 54 Tulsa 127 77 50 South Carolina 95 50 45 UL-Lafayette 113 68 45 Cincinnati 97 53 44 Georgia State 96 52 44 Kansas 126 82 44

Scott Frost’s UCF turnaround has taken off quickly. When Frost came to Orlando from Oregon, he brought Ducks outside linebackers coach Erik Chinander to be the Knights’ coordinator. UCF transformed in one season from one of the worst defenses in college football to a solid one. Then Frost’s staff landed the best Group of 5 recruiting class on Signing Day, blowing away the rest of the AAC.

Speaking of Oregon, the Ducks made an incredible hire in stealing Colorado coordinator Jim Leavitt. He got to Boulder for 2015 and significantly improved a defense that had been a dumpster fire. This past season, the Buffs’ defense became elite, with an athletic, havoc-wreaking secondary that backed up a sturdy front. This was a multi-year process, but CU grew a lot.

It’s not all bad, Rutgers.

It’s not all bad, Kansas.

2016’s 16 biggest decliners in Defensive S&P+ Team 2015 Rank 2016 Rank Change Team 2015 Rank 2016 Rank Change Missouri 10 89 -79 Akron 37 106 -69 South Florida 49 110 -61 Marshall 42 97 -55 Connecticut 32 87 -55 Bowling Green 61 115 -54 Florida Atlantic 76 128 -52 Ole Miss 23 74 -51 Navy 51 100 -49 Kent State 19 65 -46 Toledo 25 70 -45 Illinois 15 59 -44 Northern Illinois 53 94 -41 Middle Tennessee 82 118 -36 Mississippi State 38 73 -35 East Carolina 69 104 -35

Missouri was the country’s single biggest riser on offense. Unfortunately, it was the single biggest faller on defense. The defense was a little bit more inept against the pass than the run, but it was bad against both, allowing efficiency and explosiveness against the run and the pass.

USF also paired a big offensive jump with a big defensive decline, with an elite offense and terrible defense. Bulls coach Willie Taggart is now the coach at Oregon, but he’s got Colorado miracle-worker Leavitt helping as his DC.

UConn ostensibly fired Bob Diaco because he made no progress in three years. If you want to zoom in closer, that the Huskies cratered on defense might’ve been the tip of the spear. Diaco’s a defensive mind, and his team couldn’t defend.

You could say something similar for Lovie Smith at Illinois. Smith’s one of the godfathers of the Tampa 2 defense, and he led a defense-oriented Chicago Bears franchise to a handful of playoff appearances and a Super Bowl loss. He didn’t take the Illini job until after Signing Day last year, so he can only bear so much responsibility. But his D still didn’t do a good enough job to have any real shot in the Big Ten.

Wondering about your team? Here’s the whole country: