College football defensive stop rate after Week 9

Ohio State, Indiana and Oregon continue to lead the way in the Big Ten title race and look like easy picks to get into the College Football Playoff regardless of who wins the league. Michigan and USC are still ranked in the AP Top 25, too. But are we sleeping on Iowa?

The 6-2 Hawkeyes aren't ranked but are currently No. 17 in SP+ and have an opportunity to make some noise in November, led by a defense that is quickly rising up the national stop rate standings.

What is stop rate? It's a basic measurement of success: the percentage of a defense's drives that end in punts, turnovers or a turnover on downs. Defensive coordinators have the same goal regardless of their scheme, opponent or conference: prevent points and get off the field. Stop rate is a simple metric but can offer a good reflection of a defense's effectiveness on a per-drive basis in today's faster-tempo game.

Stop rate is not an advanced stat and is no substitute for Bill Connelly's SP+, FPI or other more comprehensive metrics. It's merely a different method for evaluating success on defense against FBS opponents. Here's the current leaderboard entering Week 10:

The Hawkeyes have had the No. 1 stop rate defense in October, getting stops on 88.2% of opponents' drives, and have climbed from No. 30 at the end of September to No. 6 this week after putting together a dominant performance Saturday in a 41-3 rout of Minnesota.

A week after overpowering Nebraska's defense, Minnesota couldn't get much going in Iowa City. The Gophers mustered 44 yards by halftime, went three-and-out six times and finished with three plays of 10-plus yards. Quarterback Drake Lindsey threw three interceptions and finished with a QBR of 4.3, the second worst by any Big Ten QB in a game this season. That put him just ahead of Wisconsin's Hunter Simmons, who had a QBR of 1.1 in a 37-0 loss to this Iowa defense.

Defensive coordinator Phil Parker's unit has held up well in their toughest tests. Indiana only put up 20 points on Iowa, with one of those touchdowns coming on a 24-yard drive after a Mark Gronowski interception. The Hoosiers are averaging 49 points per game against everyone else. Iowa State's lone touchdown also came after a Gronowski turnover. Rutgers did manage to put together four long touchdown drives against this defense. The rest of the Hawkeyes' opponents have struggled to score on these guys.

Iowa has held six of eight opponents under 150 passing yards, is allowing the fourth-fewest yards per play (4.03) against FBS opponents and has achieved stops on 11 of 14 fourth-down attempts. The Hawkeyes' defense has given their offense the fifth-best starting field position on average in FBS, which has helped quite a bit as this Gronowski-led offense worked to find its identity over the course of the season.

This team has a prime opportunity to pull a season-altering upset next week when it hosts No. 6 Oregon. Both teams will be coming off bye weeks and prepared for a brawl. If Parker's defense can do just enough to scrap out a stunner, we're going to be talking about Iowa as a dark horse CFP candidate.

A few more updates to note regarding this week's stop rate standings:

• Texas A&M continued its historic run of third-down dominance against LSU on Saturday night. The Aggies have allowed conversions on eight of 56 drives (14.3%) against SEC opponents this season. According to ESPN Research data going back to 2004, we haven't seen an SEC defense finish better than 22% in conference play.


• LSU gave up touchdowns on four of five second-half drives against the Aggies in a 49-25 loss that ended the Brian Kelly era in Baton Rouge. The Tigers were tied for No. 4 nationally in stop rate just two weeks ago but dropped to No. 19 in this week's standings.


• San Diego State jumped from No. 6 to No. 3 in this week's standings after a 23-0 shutout win over Fresno State. The Aztecs have won five in a row and can play their way into the Mountain West title game with big games ahead against Hawaii and Boise State.


• These were the top 10 stop rate defenses in the month of October: Iowa (88.2%), Ohio State (86.2%), James Madison (82.4%), San Diego State (81.8%), Northwestern (81.1%), Notre Dame (80%), Utah (79.4%), Texas Tech (79.2%), Western Michigan (78.8%) and SMU (77.8%).


• The bottom 10 defenses in stop rate in October: Arkansas (35.5%), NC State (38.5%), Texas State (41.7%), Air Force (41.9%), UAB (42.9%), Rutgers (43.8%), Boston College (43.8%), UL Monroe (44.4%), Navy (44.8%) and Penn State (45.2%).

Note: All data is courtesy of ESPN Research. Games against FCS opponents and end-of-half drives in which the opponent took a knee or ran out the clock were filtered out.br/]