Behind the Numbers in Super Bowl 57: Kansas City Chiefs vs. Philadelphia Eagles

We have the definitive guide to the numbers behind Super Bowl 57 and the matchup between the Kansas City Chiefs and the Philadelphia Eagles. We explore nearly every analytical angle of the game and dive deep into the unique features of each offense and how they relate to the opposing defense.

With the final game of the season and the Lombardi Trophy on the line, we have one of the best matchups in years between two elite teams that have produced remarkable numbers.

Kansas City Chiefs vs. Philadelphia Eagles

These various team-level statistics take the net result of each performance — the offensive expected points per play metric is subtracted from defensive expected points per play, and so on. The outcome here tells us that these are two well-matched, high-performance teams.

The Chiefs and Eagles are both incredibly strong units but in different ways. The Chiefs seemingly dominate in net per-play statistics, while the Eagles pull ahead on a per-drive and per-game basis. In the NFL, the drive is probably the best base unit — which is to say, we can interpret all of our data through that lens instead of on per-play or per-game bases.

The first three statistics are per play, and two of them are indexed off of expected points. Expected points look at the average points scored from a particular down, distance, and field position, and subtracts the difference between two plays to determine how many expected points were added between those plays.

It does a great job predicting NFL outcomes and can help us explain which teams have helped themselves the most with particular types of plays, like how some interceptions hurt more or less than others because they occurred deep downfield on third-and-long, instead of in the flat on 1st-and-10.

Success rate evaluates what percentage of plays gained expected points. Any play that added to the total counts as a success, while plays that reduce expected points do not. This is a good proxy for consistency because it tells us whether or not a team can, from play to play, accomplish their goals instead of relying on fluke plays like a busted coverage or tipped interception.

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EPA per play takes the average expected points gained over the course of a game and divides it by the number of plays.

Explosion rate looks at how often a team creates an explosive play, which is defined as 16 or more yards through the air or 12 or more yards on the ground.

Drives encompass all the possible events for a team. If one team is more likely to score on an individual play-by-play basis but is less likely to score on a per-drive basis, the team with better per-drive statistics will win out because you cannot score more often than the number of times you possess the ball.

Scoring rate per drive is pretty intuitive, but drive success rate is not. Here the latter refers to the ability of an offense to generate first downs (or for a defense to stop them). It takes the number of first downs (and touchdowns) generated on a drive and divides it by the number of series an offense had.

A team that generates two first downs and then kicks a field goal would have a success rate of 66.7%, while a team that generates one first down and then scores a touchdown would have a success rate of 100%.

If a team scores every 20 plays but spreads that out over five drives and another team scores every 25 plays but keeps that contained in three drives, it tells us that they likely prioritize getting first downs and getting into scoring range instead of taking explosive shots while giving the ball back.

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Having more plays per drive is only a small negative, and if a team keeps their turnovers per drive down, it’s not an issue at all. And, importantly, the first team in this example has given their opponent two additional possessions to respond.

That said, the Eagles’ advantage here is marginal. They are more likely to gain or prevent first downs and have more net points per drive, but score or prevent scores just a little bit less often.

The three opponent-adjusted per-game metrics help the Eagles, too. The opponent adjustments in this case are small, as the Eagles are ahead of the Chiefs in these categories without adjustment.

“SRS,” or Simple Rating System, takes point differential and compares it to the average expected point differential based on a team’s schedule. Then, for each team, it does that again using the new average value. And again, and so on, until the changes from run to run are small.

That closes the gap between the two, but it’s not enough to flip it in the Eagles’ favor. Game Script, which also uses points, does do that, however.

Instead of looking at the score at the end of the game, Game Script takes a look at the score for every second of every game, taking the average point differential across all time played. That produces a more granular measure that accounts for garbage time. It rewards teams for dominating early and throughout the game and captures back-and-forth games that end up looking less like the close contests they were.

It has its own problems but generally predicts future outcomes better than point differential and can be adjusted for opponents in the same way, as done here. The Eagles’ penchant for scoring early and preventing big scores puts them just slightly ahead of the Chiefs, who tend to pull away late in games they end up winning.

DVOA is both a per-play and per-game metric. It accounts for both success rate and explosiveness rate but adjusts for opponents on a per-game level to give us a season-long score. It officially stands for “Defense-Adjusted Value Over Average,” where defense just means opponent. Again, at this more granular level, the Eagles are just ahead of the Chiefs.

When the Eagles Have the Ball

By virtually every measure, the Eagles’ offense is a high-level unit, while the Chiefs’ defense is about average. The only instances where that isn’t the case comes on the side of the Chiefs’ defense, where they are well above average in preventing explosive plays and well below average in preventing first downs.

The rest of the metrics tell us how this bears out – in below-average overall performance – but it does give us some understanding of the character of the Chiefs’ defense, which uses two-high looks at a higher rate than any other defense in the league. That prevents deep passes but opens up space for short passes and runs up the middle.

The fact that the play success rate is a bit better than the EPA per play tells us that these gains tend to come in sizable chunks below the threshold of an explosive play but beyond that of a typically successful play. For the Chiefs’ defense to hold their ground, they’ll have to prevent those chunk plays – passes of 12 yards, runs of eight yards, and so on.

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The Eagles, on the other hand, are fairly even offensively and don’t rely on a particular style of play to get points. They can generate small successes play after play or win with big explosive plays. They score at a high rate, and those scores are valuable – not just field goals.

They are slightly more consistent than they are explosive, but it’s a small difference. Same with points and scoring – they don’t settle for field goals at an extraordinary rate, but they rank higher in scoring than points because they don’t always convert once they cross midfield.

It’s not a red zone issue – they rank third there – but more of a small problem in the gray area before the 20-yard line, sometimes referred to as the “orange zone” or “maroon zone” by different commentators.

In either instance, the difference in performance is relatively small, and the Eagles’ offense is operating at a high level. Given that the Chiefs’ defense has been about league average at forcing punts, turnovers, and so on, there’s not much here that tells us that the defense will dictate the flow of the game.

Eagles Passing Offense vs. Chiefs Passing Defense

In the passing game, the Eagles pick explosiveness over consistency, though they can still check down when the looks aren’t there deep. That picking and choosing is why they can still be relatively efficient down to down when the explosives aren’t there, though it still drags down their success rate a little bit.

Jalen Hurts ability to scramble can provide the passing game with a floor in terms of production. That’s why the deep-ball rate can be middle-of-the-pack and the average depth of target can be just a little bit higher than average, but the overall production in EPA per play and yards per dropback can be so high.

That tendency to scramble is one reason that the sack rate is so high, but the overall production has generally been worth it on offense. That risk aversion with a high floor also means their turnover rate on offense has been low.

This gives Philadelphia a decent success rate, but it primarily means they rely on explosiveness. Their explosion rate on dropback passes is second in the NFL, and their yards per attempt on deep balls is No. 1 in the league. The Eagles live and die by those explosive plays and just pepper in enough success to keep the chains moving.

This might also explain why their scoring rate isn’t up there with the league’s best. Philadelphia lives in volatile plays and hopes the plays in between explosive ones can do enough to keep the chains moving. It generally does that but not at the rate of elite offenses.

The Chiefs generally force opponents to throw short. They deter deep balls at a high clip, but even intermediate passes are turned into shorter passes. A lot of that has to do with their structure – they play more two-high coverages than any other team in the league, which leaves a little bit more space underneath to throw the ball and makes deep passes a little riskier.

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That’s going to be tough against the Eagles, however. Given the scrambling capabilities of Hurts and the overall strength of the run game, it will be tough to park an extra safety up top to stop deep passes when that leaves blocking advantages for the offense when running the ball.

The only two-high defense the Eagles see with any regularity is Cover 4, with two deep safeties and two deep corners. That’s not a surprise – the Cover 4 defense, which saves the deep safeties from having to do sideline coverage, can be implemented as a run-defense version of the two-high look, one that Pat Narduzzi made famous at Michigan State.

Without needing the range of a Cover-2 safety, the two “deep” safeties can park themselves closer to the line of scrimmage while defending the deep ball.

That’s made sense – the Eagles rank 11th in net yards per passing attempt and tenth in EPA per dropback against Cover-4. They rank third in net yards per attempt and eighth in EPA per play against the other styles of two-deep safeties.

Their scramble rate has been higher on those other coverages, too, making Cover-4 look a bit more palatable than other styles of coverage.

The Chiefs might consider moving away from some of their base coverages and pulling some lessons from Narduzzi’s defense in order to have all hands on deck to take on Hurts in the running game, even as it increases the number of one-on-ones to the outside against Philly’s talented receiving corps.

Eagles Run Offense vs Chiefs Run Defense

The threat of the quarterback run is why we were concerned that the San Francisco 49ers’ excellent numbers against the run wouldn’t matter in the NFC Championship Game. San Fran they didn’t face running quarterbacks all that much and didn’t do well when up against that kind of player.

The Chiefs have faced their fair share of quarterback runs, though it’s not because they played the Baltimore Ravens, New York Giants, or Eagles this season. The quarterbacks who have run the ball most against them include Josh Allen, Malik Willis, Joe Burrow, Bryce Perkins, and Jarrett Stidham.

The Chiefs’ history against the quarterback run isn’t quite the same as going up against an offense systemically designed to take advantage of the extra blocker afforded to teams with a running quarterback.

Even so, eliminating quarterback scrambles from the data doesn’t change anything – the Chiefs have faced the fifth-most snaps against designed runs this season and have still been relatively successful against them.

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The biggest issue will be the cohesiveness with which teams like the Chicago Bears, Atlanta Falcons, Giants, Ravens, and Eagles incorporate the running quarterback into their entire offense. Aside from simply freezing a defender in order to gain a gap in the running game, each of those offenses implements it in their passing game as well, holding or optioning off of defenders in coverage to run an effective RPO.

How the Chiefs fare against that is an open question.

Otherwise, the Chiefs are generally fine against the run, though they somewhat predictably don’t have the ability to produce tackles-for-loss at a high rate because they pull a defender out of the box in order to defend deep passes. They still get in their run fits and don’t sacrifice too much in the running game, and, importantly, prevent explosive plays and first downs.

When the Chiefs Have the Ball

For all the criticism that defensive coordinator Jonathan Gannon has received over the past two years, it’s clear that the Eagles’ defense has been beyond capable when it comes to keeping offenses off-schedule and off-track.

Head coach Nick Sirianni, in particular, prizes turnovers and explosive plays. While every head coach talks about the importance of causing turnovers and preventing explosive plays on defense, it seems as if the Eagles are willing to sacrifice other elements of the defense in order to accomplish that goal and really commit to the idea that this is a particular priority.

Relative to other high-level teams, the Eagles don’t have a particularly high success rate on a play-to-play level when it comes to stopping opposing offenses.

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But they do a great job at preventing explosive plays and a decent job restricting points on a drive-to-drive basis. They rank third in the NFL in turnovers per drive and third in the NFL in field goals allowed per drive.

The Chiefs’ offense doesn’t need much introduction. It is consistent and explosive. They score points and avoid turnovers. There is no total offensive metric where they don’t rank first or second, whether that’s on a per-play basis, per-drive basis, or per-game basis.

The unique thing about the Chiefs has been their ability to maintain a high rate of explosive plays while still being the most consistent team in the league when it comes to generating first downs or getting more yards on a typical play than any other team in the same situation.

Chiefs Pass Offense vs Eagles Pass Defense

It’s hard to overlook the fact that this might be the key matchup of the game. The number one passing offense against the number one passing defense by a few different metrics. It’ll be difficult to get a good sense of who has the absolute advantage in this case.

It should be noted that the Eagles passing defense may look great in opponent-adjusted numbers, but those opponent adjustments take into account total team performance, not the individual quarterbacks they were up against. The Eagles faced a fortuitous slate of bad or backup quarterbacks throughout the season, making their excellent defense look a little better than it actually was.

On average, QBs they faced in wins would rank 24th in a PFF/EPA composite. The Eagles are good but you'd be better served arguing that they beat bad teams by the amount good teams are supposed to than by pointing to record as if Dallas going 12-5 somehow makes Cooper Rush good https://t.co/VQWim5hou7 pic.twitter.com/xaQyq9qcmX

— Arif Hasan, but NFL 🏈 (@ArifHasanNFL) January 30, 2023

Nevertheless, a secondary that includes Darius Slay, James Bradberry, and C.J. Gardner-Johnson is worthy of serious respect. Not only that, the Eagles rank second in pressure rate produced and in sack rate on defense.

They also happen to rank first in pass rush win rate, an ESPN statistic that looks at how often a defense gets past the pass protection and into the pocket within the first 2.5 seconds of a play regardless of whether or not there’s pressure or a sack.

It predicts pressure rate and win rate better than actual pressure rate does and provides a good understanding of how defensive lines work.

Still, one has to understand that the Chiefs’ offensive line has been quite good. Trading for Orlando Brown, signing Joe Thuney, and drafting Creed Humphrey did worlds of good for their pass protection, and Andrew Wylie’s development at tackle has been an excellent story in its own right.

The reason that the Chiefs have a high pressure rate is that Patrick Mahomes is holding on to the ball longer than he ever has in his career and ranks fifth in the NFL in longest time to throw.

That usually means a high sack rate, as it does with Jalen Hurts – who ties Mahomes in time to throw – but Mahomes’ sense of when to get rid of the ball is better than anyone else in the league.

So the Eagles will have to test their ability to convert pressure into sacks and finish – they’re, unsurprisingly, also the best in the league – against Mahomes’ ability to prevent pressure from turning into negative plays, including sacks.

We’ve seen Mahomes stumble in those situations, like in his last Super Bowl appearance. But even then, he played spectacularly and was more let down by a receiving corps that couldn’t win contested catches than he was by his own proclivity to hold on to the ball. Beyond that, he’s been up against defenses that can finish sacks well, and he’s come out on top.

It should be a fantastic battle and is likely the fulcrum point of the game. The side that comes out ahead in this matchup will almost certainly win the game.

Chiefs Run Offense vs Eagles Run Defense

The Chiefs and the Eagles have both neglected investment here, and it shows. That said, the Chiefs have still been able to maintain a high level of play in the running game, especially with the emergence of Isiah Pacheco, while the Eagles have floundered in run defense.

Philly’s run defense has improved substantially since returning Jordan Davis from injury. Since Week 13 and his return to the lineup, they’ve ranked 21st in yards per carry, fifth in defensive rush success rate, 20th in tackle-for-loss rate, eighth in EPA per snap, 13th in first-down rate, and eighth in rush-defense DVOA.

The only two places where the Eagles have stepped back are in explosive rush rate (23rd) and fumble rate (12th). While still giving up the occasional explosive run, Philadelphia’s rush defense has firmed up as they’ve increased Davis’ role in the defense while supplementing him with Ndamukong Suh and Linval Joseph.

It hasn’t been an amazing showing, but the Eagles have been able to mitigate a big weakness. The Chiefs have still found ways to be successful in running the ball, though. And if the Eagles relax in the run game, it could doom them.

The Super Bowl this year does not feature an underdog ready to upset the natural order of the NFL. It does not include a team that suddenly got hot in the playoffs. It features the two best teams in the NFL who are good in nearly every phase of the game.

It should be fun.