by Andrew Healy

At its best, sports analytics is like good science. New evidence comes in and forces everyone to rethink what they thought they knew. Nearly a hundred years ago, astronomers saw evidence of relativity and suddenly gravity wasn't so simple. The apple didn't just fall towards the center of the Earth. Curved space pulled it. Newton was out and Einstein was in.

A century later and equally significant, football analytics research would establish that offense is more important than defense. More specifically, overall team quality is four parts offense, three parts defense, and one part special teams. Sunday's game between the Packers and Bills seemed to illustrate that idea. The Packers came in with the NFL's top-ranked offense and No. 1 passing offense while the Bills entered the game with the second-ranked defense by DVOA, and No. 1 pass defense. Consistent with the supremacy of offense, the Packers came into Buffalo with a 10-3 record and as Vegas's favorites to win the Super Bowl. The Bills were 7-6 and on the fringes of the playoff picture.

But just like relativity left open questions at the atomic level, the offense-first football theory can't quite explain what happens in those rare cases when the best passing defense goes up against the best passing offense. That has happened 17 times now since 1991, 11 times in the regular season and six times in the playoffs. And what happened to Aaron Rodgers on Sunday actually isn't that out of line with what happened in those other 16 matchups. The top-ranked passing defense has consistently gotten the better of the top-ranked passing offense.

On Sunday, Aaron Rodgers came into the game as the top-ranked quarterback by DVOA. He was averaging 9.79 adjusted net yards per attempt (ANY/A), an amazing number even in this era of inflated quarterback stats. Against Buffalo, Rodgers threw for 1.98 ANY/A, his worst performance in his career as a starter in a game that he finished.

A similar pattern holds across the ten regular-season matchups from 1991-2013 that matched the top-ranked passing offense for the year against the top-ranked passing defense. On average, the passing offense dropped about 3 yards in ANY/A from how well it performed in other games to how well it performed against the best passing defense.

When the Irresistible Force Meets the Immovable Object, 1991-2013 Completion% TD% INT% Y/A ANY/A Top-Ranked Offense vs. Top-Ranked Defense 53.8% 3.8% 3.3% 5.28 4.56 Top-Ranked Offense Vs. All Other Defenses 63.3% 6.1% 2.0% 7.42 7.71 All Other Offenses Vs. Top-Ranked Defense 53.2% 3.2% 4.2% 4.75 3.48

To put those numbers in perspective, the drop in ANY/A for top-ranked passing offenses when they face the best pass defense is about equivalent to going from Tom Brady this year to Geno Smith.

Note that three of the earlier cases involved teams in the same division, and thus two games in the same year: Washington and Philadelphia in 1991, San Francisco and New Orleans in 1992, and Indianapolis and Miami in 2000. These differences stay almost exactly the same if we don't include those years.

Thus, great passing offenses like the 2014 Packers often fall flat against top-ranked passing defenses like the 2014 Bills. Perhaps surprisingly, the top-ranked passing defenses have only performed a little bit worse against the top passing offenses than they have against the rest of the league. On average, the top pass defenses have given up just about one more ANY/A to the best passing offenses than to the rest of the league.

The Bills' dominance of the Packers' offense also fits with what happened in the six playoff matchups. In each case, the dominant offense averaged somewhere 7.81 and 8.87 ANY/A over the regular season. In only one of the six playoff games did the offense exceed 6.0 ANY/A, which is about what Mark Sanchez has posted this season. Two of those games had historically good passing offenses that were obliterated by top-ranked defenses. In 1999, the Buccaneers held the Greatest Show on Turf Rams to 11 points and five fewer ANY/A than their season average. In last year's Super Bowl, the Seahawks did about as well against the Broncos.

No. 1 Pass Offenses Vs. No. 1 Pass Defenses in the Playoffs Regular Season ANY/A Playoffs ANY/A vs. No. 1 Pass Defense 1999 NFC Championship Game (STL vs. TB) 8.31 3.33 2003 AFC Wild Card (TEN vs. BAL) 7.81 1.69 2006 Super Bowl (IND vs. CHI) 7.93 5.49 2008 AFC Divisional Playoff (SD vs. PIT) 8.04 7.44 2009 AFC Divisional Playoff (SD vs. NYJ) 8.30 5.07 2013 Super Bowl (DEN vs. SEA) 8.87 4.18

The Bills outdid even those two memorable performances on Sunday, holding Aaron Rodgers to eight ANY/A below his historic pace. And more than just the extent of Buffalo's dominance in pass defense, the way in which Buffalo accomplished that success was surprising. Buffalo leads the league both in sacks (with 49) and Adjusted Sack Rate, but they had only one sack of Rodgers (the strip sack on Green Bay's last offensive play) and three other quarterback hits on the day. The Bills mostly played coverage. According to my charting, the Bills blitzed the Packers just six times, in keeping with their strategy for most of the season.

More than the pass rush, the seven men in coverage for Buffalo controlled the game. While Rodgers was out of sync with his receivers early and those receivers were credited with seven drops (the most for any team in one game since 2008), the Buffalo linebackers and secondary gave little space to Packers' receivers. OK, yes, there was this almost unbelievable drop from Jordy Nelson that would have helped Rodgers have a different stat line.

Overall, however, the number of drops probably doesn't give the Bills' secondary enough credit. Rodgers' second interception also got labeled a drop when it was caused by excellent coverage from Ron Brooks. Brooks did a great job undercutting an attempted pick from Davante Adams and then blanketing Jarrett Boykin.

The Bills had that kind of close coverage on Packers' receivers all day. As a team, the Bills were credited with ten passes defensed. Safety Bacarri Rambo (two interceptions), linebacker Nigel Bardhan, and Stephon Gilmore each had two. Although he dropped a potential pick-six, Gilmore had a very good day. I had Rodgers going 1-of-9 for 6 yards when throwing in Gilmore's direction.

[ad placeholder 3]

For Green Bay going forward, Sunday's struggles against the Bills might not mean that much. Top-ranked passing offenses like the 1991 Washingtonians, the 1995 Cowboys, the 1998 Broncos, the 1999 Rams, and the 2006 Colts all won the Super Bowl despite struggling to varying degrees in games against the top-ranked pass defense. While great pass offenses lose a surprising number of battles to top-ranked pass defenses, those great passing teams are still the ones most likely to win the war.

If They Only Had a Quarterback

After two weeks of largely shutting down the best two passing games in football, the Bills have surged ahead of the Lions into first place in overall defensive DVOA. It doesn't take analytics or a football Einstein to tell us why the Bills are still just 8-6. Kyle Orton is not very good. The Bills overcame more mediocrity from Orton on Sunday, but their ineffective offense is the reason that they remain on the outside of the playoff picture.

DVOA Off Def ST TOT BUF -34.2% -50.1% 33.6% 49.5% GB -10.5% -21.1% -22.8% -12.2% VOA Off Def ST TOT BUF -32.9% -29.3% 33.6% 30.0% GB -28.1% -31.4% -22.8% -19.5%

It's pretty incredible that the Bills won with how little they got from their offense, and in particular from Orton. Boobie Dixon (have to love anybody with that first name on a football field) had a few impressive runs. But Orton's successes were mostly limited to a long completion on a defensive breakdown to Bryce Brown and a late-game third-down conversion to Scott Chandler.

[ad placeholder 4]

For the day, Orton matched Rodgers's 17.2 QBR. For the year, Orton's 39.3 QBR puts him in 27th place out of 30 qualifying quarterbacks. He does a little better by DVOA because of positive opponent adjustments, but he's still 27th (out of 40). Overall, the Bills offense is very good at setting up punts. Only five teams (Oakland, Jacksonville, Cleveland, Arizona, and Tennessee) have punted more often than the Bills. In offensive drive success rate, which measures the percentage of down series that result in a first down or touchdown, the Bills rank 29th, ahead of only Oakland, Jacksonville, and Tennessee. By that same statistic, the Bills' defense ranks first even though Buffalo has faced the third-toughest slate of opposing offenses in the NFL.

All of this is to say that what the Bills' defense has accomplished in recent weeks against great offenses is as impressive as what Seattle's has done against mediocre-to-bad ones. The Bills won't get the same amount of attention because the win-loss record will always drive the narrative. And that record has a relatively low ceiling as long as the defense and special teams have to carry the Kyle Orton albatross to wins where the offense averages 4 yards per play.