Let's say you're new Florida State defensive coordinator Mark Stoops.
You've inherited a unit that is a shadow of the nasty bunch that used to terrorize opponents back in the days of Peter Boulware and Marvin Jones. Now, you're looking at a D that gave up 6.7 yards per play last year, 115th in the country. That represents a 43 percent increase from 2008, when the Seminoles allowed 4.7 yards per snap.
Newly installed head coach Jimbo Fisher didn't hire you to maintain the status quo. Thankfully, it can't get much worse. The real question: How much better can it get?
Fans in places such as Tallahassee and Champaign are counting on purported saviors like Stoops and first-year Illinois offensive coordinator Paul Petrino to instantly upgrade their sides of the ball. If 2009 is any indication, they better temper their expectations.
Using data from the website cfbstats.com, I calculated the percentage change in both offensive and defensive yards per play for every D-I program from 2008 and 2009. Extreme makeovers were few and far between.
(Click here to view a spreadsheet with the statistics that I compiled. If you have any questions about the numbers, feel free to e-mail me or comment below.)
The 12 teams that showed the most improvement in average yards gained per play from '08 to '09 -- the top 10 percent of D-I teams -- experienced increases between 44.4 percent (Central Florida) and 24.5 percent (Hawaii). The largest increase in terms of actual yards per play belonged to Idaho (2.0).
As you would expect, 11 of the top 12 teams with the biggest percentage gains finished '08 below the national average in offensive yards per play (5.5).
The bottom 12 squads saw their averages drop anywhere from 32.8 percent (Rice) to 15.3 percent (Texas) from one year to the next. Ball State had the biggest absolute decline, dropping 2.2 yards per play.
Not surprisingly, all but one of the bottom 12 were above the national average in offensive yards per play in '08.
The top 12 teams in terms of defensive improvement decreased their yards allowed per play by anywhere from 32.2 percent (Nebraska) to 12.9 percent (Kansas State, San Diego State). Of that group, nine had marks above the national average in 2008 (5.3). Nebraska shaved off nearly two yards per play, the most improvement in the nation.
The bottom 12 squads saw their averages drop anywhere from 42.6 percent (Florida State) to 21.7 percent (UConn) from one year to the next. All but two of the bottom 12 were above the national average in defensive yards per play in '08. FSU gave up an additional two yards every play, the worst year-to-year change in the country.
It's important to again note that these are essentially best- and worst-case scenarios. It's nice to think that your favorite team could cut its defensive average down 20 percent in 2010, but the reality is that four out of 120 D-I teams managed to accomplish that last season.
So let's return to the FSU example. For the Seminoles to get back to their '08 level of performance on defense, it would require cutting two yards off their per play average, a 30 percent decrease. Only one team in the country was able to achieve that level of improvement in 2009, and it had Ndamukong Suh at nose tackle.
Based on the numbers from last year, a more reasonable expectation would be something on the order of a 10 percent cut in the upcoming season, which translates into an average of about six yards allowed per play. That's still a considerable amount above the 2009 national average of 5.4.
Not good, but it's a start.