For A Passing League, The NFL Still Doesn’t Pass Enough

The 3-point revolution in basketball was driven in large part by the finding that the three has a higher expected value than a midrange jump shot.²² While the math is simple and clear, the revolution didn’t occur overnight — or even in the first few decades after the 3-point line was introduced. Because those longer shots don’t go through the hoop as often as midrangers, missing a shot feels like failure. There is a slightly counterintuitive aspect to it.

Now imagine a world where 3-pointers aren’t simply worth more as measured by expected points, but where they also go through the hoop more often. The benefits of the three would be stunningly obvious. We might even question the competence of coaches and teams that didn’t attempt them as much as possible.

That’s where the NFL is currently living. The NFL is a passing league that somehow doesn’t pass enough. NFL teams know the medicine works yet stubbornly refuse to take a clinically effective dose.

To be clear, teams are certainly passing more often than they used to. Leaguewide passing attempts per game have risen from 32.3 in 2008 to 34.2 last year, and the increase in volume has not been accompanied by a decrease in efficiency. Leaguewide yards per attempt have increased slightly from 6.9 to 7.0, and more touchdowns are being scored by passing relative to running than at any time in league history. Completion percentage is up from 61.0 percent to 62.1 percent, and the interception rate has fallen from 2.8 percent to 2.5 percent. Yet despite all these positive indicators, teams remain unwilling to break old habits and throw in many classic rushing situations.

The biggest culprit is first down, the most traditional run situation. It’s here where NFL coaches are consistently missing an opportunity to pass, particularly against defenses that have stacked the box or are playing at least seven defenders close to the line of scrimmage. I’m calling these situations FANS — First (down) Against Neutral or Stacked (boxes). FANS includes plays in which the defense brings extra men close to the line of scrimmage, clogging running lanes and daring the offense to run the ball. I analyzed plays from the 2017 season using men-in-the-box data from analytics firm Sports Info Solutions and play-level data courtesy of Ron Yurko, a Ph.D. student in statistics at Carnegie Mellon University. To more accurately represent regular game play and eliminate noise, I limited the sample to snaps outside the red zone when the opposing teams were within 7 points of each other.

With seven to nine men near the line of scrimmage and the subsequent dearth of extra defenders in the secondary, we’d expect passing to be effective in these situations. That’s just what we found. Last season, 30 of 32 teams were more successful passing than running on FANS as measured by success rate.²³ And passing wasn’t just a little more successful than running. The difference in passing success was large: 27 teams had a success rate that was at least 10 percentage points higher when passing on FANS than running; 14 teams were more than 20 points better. The league average difference of 19.3 leaned wildly toward passing.

Even accounting for the potential negative outcomes of a dropback like sacks and interceptions, passing on FANS keeps a team “on schedule”²⁴ in the down and distance more often than a run. Incredibly though, there were 31 NFL teams last season when facing this situation on first down — looking down a defense that was clearly gearing up to stop the run — that chose to run more often than they passed. Here’s the same table as above, now sorted by the frequency of play type.

The only team in the NFL that passed more often than it ran in this situation was also the only team to lift the Vince Lombardi Trophy. Doug Pederson and the Eagles broke from the flock and dropped back to pass the ball 55 percent of the time — which was in some ways part of a larger strategy to break from convention. “A lot of NFL coaches have traditionally been averse to taking risks,” Pederson writes in his new book, “Fearless.” This desire to zig when the other teams were zagging showed up in Philadelphia’s fourth-down conversion attempts and two-point tries — two darlings of the statistical community.

What about other more traditional passing downs? Second-and-long certainly qualifies. The league still runs as much as they pass on that down and distance, with just four teams boasting a higher success rate rushing than passing.

The average rushing success rate on second-and-long for the league is just 27 percent verses 46 percent for passing, a massive difference. The average of 18.7 percentage points in pass-run differential is only slightly lower than the 19.3 percentage points on first down. And this is despite teams passing 11 percentage points more often than on first down.

If we combine the two down-and-distance situations, a clear picture emerges showing the NFL’s reluctance to actually pass when the situation warrants it.

The choices made on early downs are meaningful. The Oakland Raiders won six games in 2017 while leading the league in share of rushing on first- and second-and-long against a crowded box, at 69 percent of the time. If the Raiders had instead passed on 60 percent of those occasions, they would have seen a swing of 19.5 expected points, good for about half a win.

Sometimes gains from passing aren’t absolute gains. Poor offensive teams can benefit from passing even if only to mitigate against the greater loss from running the ball. Last year, the Tennessee Titans employed a run-first, smash-mouth offensive strategy that saw them rush in these FANS situations 61 percent of the time. Both running and passing plays were losing propositions for them, but passing was still the least worst option. Had they flipped the script and passed 61 percent of the time, the Titans would have saved themselves 7 expected points, good for about a fifth of a win.

Thursday night, the Atlanta Falcons kick off the NFL season against the Eagles in an NFC divisional round rematch. Last season, Atlanta was successful on a league-leading 63 percent of passing plays on first-and-10 and second-and-long against neutral or stacked boxes. The Falcons also led the league in pass-run success differential at 34 percentage points. Inexplicably, they ran the ball more than half the time. Had the Falcons passed at a level commensurate with their success rate, they would have earned 35.9 more expected points over the course of the year, good for an additional win.

Like most of the rest of the NFL, Atlanta can improve its chances greatly by taking a page from the Eagles. On Thursday, we’ll see if they learned from their adversary this offseason. In the league that struggles to embrace change, it’s no sure thing.

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