Does home-field advantage still exist in the NFL?

Home-field advantage has been a baked-in NFL trend for as long as there's been an NFL. The familiar surroundings, lack of travel, and crowds howling with full-throated support all are well-known factors that have made it beneficial to play a game in a home stadium. But is that edge going away? If so, why?

The 2020 season was the first in NFL history in which home teams finished with a losing record (127-128-1). It was easy to isolate the variable: Due to COVID-19 protocols, most stadiums were either empty all year or limited attendance, which robbed home teams of a clear advantage.

Stadiums are full again in 2021. Yet through the season's first seven weeks, home teams are still struggling. Excluding the three neutral-site games (two in London, plus the Green Bay Packers-New Orleans Saints opener that was moved to Jacksonville because of Hurricane Ida), home teams are just 50-54 with roughly 40% of the season already in the books. That's a winning percentage of just .486, which is way below the median seasonal winning clip of .576 that home teams posted from 1970 to 2019.

So, what's going on? If screaming fans are back, why has the advantage taken such a dramatic dip? There appear to be several reasons: Offenses are more efficient, teams are being more aggressive on fourth down, referees are calling fewer penalties, and two clubs that were absolutely dominant at home aren't doing so well this year. Betting lines are being affected, too. The big question is whether the trend of visiting teams will continue as the season progresses.

Efficient offenses

In a Twitter thread last week, former Philadelphia Eagles assistant coach and analytics specialist Ryan Paganetti discussed the possibility of visiting teams benefiting from being more successful on first and second down, which would lead to shorter yardage in third-down situations.

The numbers bear this out. According to data collected using nflfastR through Week 6, visiting offenses have indeed improved their success rates on early downs from 2019 to 2021 when passing. This is true whether success rate is defined by analyst Ben Baldwin's method (any play with positive expected points added) or analyst Warren Sharp's (gaining at least 40% of yards-to-go on first down, 60% on second down, 100% on third and fourth down).

In 2019, visiting offenses had an early-down success rate on passing plays of just 47.2%, according to Baldwin's definition, and 48.9%, per Sharp's. In 2020, those figures improved to 49.7% and 51.5%, respectively, and that trend has continued into 2021: 50.9% (Baldwin) and 52.7% (Sharp).

As Paganetti pointed out, an increase in shorter to-go scenarios on third downs means crowds are less involved, which makes it easier for offenses to set protections while also making it less likely for those offenses to face exotic blitzes and pressures.

Fourth-down aggressiveness

The notion that it's often better to go for it on fourth down rather than punt or attempt a field goal has long been supported by reams of data. NFL coaches are finally buying in, and that aggressiveness is helping visiting teams level the playing field.

Teams are averaging just 3.7 punts per game - the same as in 2020, and roughly half a punt per game less than as recently as 2019. In fact, punts have become increasingly more infrequent for a least a decade: Their usage has steadily declined since 2011, when teams were averaging 4.9 per game.

In turn, there are now far more fourth-down scrimmage plays than there used to be. Teams are averaging 2.79 fourth-down scrimmage plays per game. That's an increase of more than 9% from 2020 and a jump of nearly 24% since 2019. It's also another trend that's been gradually on the rise: As far back as 2011, teams were averaging just 1.68 fourth-down scrimmage plays per game - a whopping 44% less than in 2021.

This, in turn, has led to fewer possessions per game. In 2018 and 2019, teams averaged a combined 22.4 drives per game. However, in both 2020 and 2021, that number has dipped to 21.7 - a decrease of more than 3%.

Why this matters: As Paganetti also noted, fewer possessions can create more variance in a game's outcome.

Penalties

NFL director of data and analytics Michael Lopez shared some info last week that showed delay-of-game penalties by visiting teams and pre-snap defensive fouls were down in 2020 - factors he acknowledged were likely influenced by empty stadiums:

According to individual play data collected with nflfastR this season, delay-of-game penalties through Week 6 have again diverged for home and visiting teams, with the former averaging 0.186 per 100 plays versus 0.287 for the latter. The disparity is similar to what it was in 2019 when hosts averaged 0.170 delay-of-game infractions per 100 and visitors averaged 0.215. So crowds again appear to be affecting away teams' ability to get a snap off in time.

But other penalty trends tell a different story. Defensive offside and neutral-zone infractions against visiting teams continue to decline, with defensive offside down more than 20% - to 0.186 per 100 from 0.233 - since 2019, while neutral-zone infractions have dropped more than 47% - 0.118 from 0.224 - in the same span. Both offside (down 22%) and neutral-zone penalties (down 46%) are also decreasing for home teams, but it's significant that visitors are shooting themselves in the foot far less with these fouls.

Interestingly, though, offensive holding penalties since 2019 are down by 18% for home teams but slightly up by 1.4% for visitors, so that doesn't appear to be a factor that's benefiting road teams.

End of dominance

One thing has been essentially guaranteed for years: the New England Patriots and Seattle Seahawks won at home. That's no longer the case, and it's having a profound impact on this year's home-road splits.

From 2001 to 2019 - during the Patriots dynasty - New England was 127-25 in regular-season games in Foxboro. That's good for a winning percentage of 0.836, and it was also a full 15 games better than any other home team in the NFL.

Likewise, the Seahawks were 55-17 (.764) at home from 2012 to 2020, a span that includes Russell Wilson's tenure as quarterback. Only the Patriots' 59-13 mark (.819) during the same stretch was better.

Two years after Tom Brady's departure and with Wilson now injured, things are a little different. The Pats have already played five home games in the season's first seven weeks, yet their thrashing of the hopeless New York Jets on Sunday was their first home victory. The Seahawks, meanwhile, fell to 0-3 at home with Monday night's loss to the Saints. That's a combined 1-7 record as hosts for two of the most traditionally dominant home teams in the NFL.

Betting lines

Vegas has caught on to the trend of visiting teams playing better.

According to data pulled from Pro Football Reference, road teams were designated as betting favorites an average of 35.7% of the time from 2010 to 2019. That figure jumped to 41.8% in 2020, and it stayed roughly that high (41.7%) through the first six weeks of 2021.

Similarly, according to betting data at KillerSports.com, road favorites had an average spread of 4.2 points from 2010 to 2018. In 2019 and 2020, road favorites laid an average of 5.0 points. Through seven weeks this year, they're giving 4.4 points.

Is the home field going to be a watered-down advantage from now on? Time will tell, though home teams were 9-4 straight-up in Week 7 to get close to .500 again.

Dom Cosentino is a senior features writer at theScore.