The most exciting defenses to watch are the ones that specialize in raising hell. We have a statistic to tell us which teams are the best at this kind of specialization. It's appropriately named havoc rate, and just as it sounds, it determines how often a defense wreaks havoc on opposing offenses.

Havoc rate measures the percentage of plays that end in a tackle for loss (including sacks), forced fumble, or tipped/intercepted pass. See more on Bill Connelly's havoc rate and other advanced stats here.

The national average was 15.8 percent for the 2014 season, and the defense best at raising hell was Clemson, which finished almost two percentage points better than second place TCU.

Here are 2014's full 1-to-128 rankings, all from the Football Study Hall database, followed by a glimpse at the top 10 power-conference defenses.

Top 10 powers

1. Clemson

195 havoc plays, 23.2 percent havoc rate. Four returning starters for 2015.

The Tigers were expected to have a ferocious style under Brent Venables, and that's exactly what they did. They were particularly good up front, finishing with 17 more tackles for loss than anyone else. Now who's gonna replace those two first-round draft picks?

2. TCU

206 havoc plays, 21.6 percent havoc rate. Five returning starters for 2015.

TCU was able to outpace its conference counterparts by a wide margin. The next best in the Big 12, according to havoc rate, was Baylor, who ranks 26th nationally. That's due in part to its 4-2-5 defense, key to stopping to up-tempo offenses.

(The top non-power, Louisiana Tech, ranked No. 3 overall. Its coordinator? Fired Texas DC Manny Diaz, who's now back at Mississippi State.)

3. Virginia

173 havoc plays, 21 percent havoc rate. Four returning starters for 2015.

The front seven wasn't particularly successful in opposing backfields. But the secondary defended more passes than any other in the country. The entire linebacker corps leaving puts more pressure on both the front and back.

4. Florida

182 havoc plays, 20.9 percent havoc rate. Seven returning starters for 2015.

Nobody doubted Will Muschamp's defensive chops, and that's why he was immediately tabbed to be Auburn's coordinator after being fired as Gators head coach. Florida's star secondary will be loaded again, including potential No. 1 pick Vernon Hargreaves III.

5. Virginia Tech

180 havoc plays, 20.7 percent havoc rate. Eight returning starters for 2015.

Defense is rarely Virginia Tech's problem.

The secondary and defensive front were both very good. With star defensive end Dadi Nicolas and cornerback Kendall Fuller coming back, Virginia Tech's defense should be here again next year.

6. Arkansas

167 havoc plays, 20.3 percent havoc rate. Six returning starters for 2015.

Arkansas held Alabama and Mississippi State to 31 total points before shutting out LSU and Ole Miss in back-to-back games. If the Hogs get a balanced offense, look out.

7. Louisville

171 havoc plays, 20.2 percent havoc rate. Four returning starters for 2015.

Louisville's defense gave up a lot of points, but was deceptively efficient, finishing in the top 15 in defensive S&P+. The Cardinals have a lot to replace after seeing six defensive players get drafted.

8. Michigan State

162 havoc plays, 20.1 percent havoc rate. Seven returning starters for 2015.

Michigan State has become known for its defense, especially since holding Michigan to negative-48 rushing yards in a single game. The Spartans are now evolving, thanks in part to Baylor. Can MSU remain itself despite the loss of coordinator Pat Narduzzi, who took the head job at Pitt?

9. Ohio State

206 havoc plays, 20 percent havoc rate. Seven returning starters for 2015.

The Ohio State offense stole the show during the College Football Playoff, but its defense became accustomed to big plays ending with a Joey Bosa shrug.

(Photo via Thomas J. Russo-USA TODAY Sports)

With the totally unfair Bosa and many more returning, Ohio State is likely to return to this list.

10. Penn State

163 havoc plays, 19.2 percent havoc rate. Six returning starters for 2015.

Penn State has been offensively challenged, but the Nittany Lions' defense was stout. The defense should continue to get stronger as the program recovers from sanctions, but it needs to replace its best player, linebacker Mike Hull.