Why Home Field Advantage Is Not What It Used to Be

An unsettling new reality is creeping across the landscape of professional sports: Anyplace may be as good as home.

Ask the spectators in New Orleans, Philadelphia and Foxborough, Mass., following the first round of the N.F.L. playoffs. Or the baseball fans in Houston and Washington during the World Series last October.

The home-field advantage was once so airtight a principle in sports. Data supported it. Coaches trumpeted it. Stadium pyrotechnic crews fueled it. The credo was Las Vegas oddsmakers automatically cooked in a three-point cushion for N.F.L. home teams and adjusted their lines from there. But enough gamblers have been burned this season to question whether playing fields are leveling.

In the N.F.L., a variety of factors appear to be contributing to a steady shift in the competitive balance since the 1990s, when home teams won 59.8 percent of games, including nearly three-quarters of their postseason games. For instance, in 1999, the N.F.L. added a check on referee influence by instituting instant replay and coaches’ challenges. The next season, the home winning percentage dropped from 59.6 percent to 55.6. It was 51.7 percent this season, the lowest mark since 1972.

Some point to how coaches have better simulated stadium environments during practices. Others credit the players’ luxury travel arrangements. Still others note the rising popularity of meditation apps, sleep coaches to help guard against jet-lag and sports psychology. A few have an even stranger culprit: The rise of virtual-technology training to let athletes act out the scenarios they might encounter.

All of that can help teams manage the most hostile work environments, like the New Orleans Superdome, where the crowd noise reached 125 decibels last Sunday, comparable to a jet at takeoff.

“Loudest it’s been in any stadium this year,” Minnesota Vikings receiver Stefon Diggs said.

The Vikings won, 26-20, in overtime, sending Saints fans home, hoarse and heartbroken, for the second year in a row.

You’ll still never get a football coach to admit he would rather play a big game on the road, said Bill Cowher, the CBS analyst and former coach of the Pittsburgh Steelers. But he knows there are certain locker rooms with the right alchemical makeup to learn to love the road’s disadvantages, as his team did in 2005, when the Steelers were 9-2 on the road and chose to wear road jerseys in the Super Bowl.

With so much more money available, road teams have the luxury of bringing many of the comforts of home along with them — from massage therapists and chefs to condiments and toilet paper.

“It’s so efficient,” Geoff Schwartz, a former N.F.L. lineman and Sirius XM commentator, said of the travel routines. Little gets overlooked, including how players combat inflammation on long flights. “Guys wear compression tights or they eat better. They’re just so much better trained and more in tune with their bodies.”

The Seattle Seahawks are this year’s favorite road warrior. After winning at Philadelphia last Sunday, the Seahawks improved to 8-1 on the road. At home at CenturyLink Field the Seahawks were 4-4, even though the stadium is designed to harness crowd noise so effectively that, at one point this season, an opposing lineman was flagged for unnecessary roughness because he couldn’t hear the referees whistle the play dead.

“It’s harder to play when you can’t hear. That’s a fact,” Coach Kyle Shanahan of the San Francisco 49ers said this week. “But that definitely doesn’t mean you can’t win, as everyone proves each week.”

To be sure, any attempts to find a surefire trend of a declining home field advantage can be a fraught endeavor that might depend on the size of the sample being studied. For instance, home teams have won 75 percent of divisional round games since 2010 — and 74 percent since 1990 — so maybe hold off on betting the farm on the Seahawks, the Vikings, the Titans or the Texans. Also, studies have shown even random outcomes can be streaky. Flip a coin 20 times and don’t be surprised if it comes up tails seven times in a row.

Yale economist Tobias Moskowitz said the psychology of the referees may be the most likely factor contributing to the winnowing of the home-field advantage.

Crowds have only a modest effect on professional athletes’ performance over time, Moskowitz said. N.B.A. free-throw shooting percentages are about the same at home and away, “down to the decimal point,” he noted. But when fans were barred from attending games in Italy’s top soccer league, Serie A, after an outbreak of violence in 2007, the home-field advantage fell by 80 percent.

“It wasn’t that the players played any differently,” said Moskowitz, co-author of the book “Scorecasting,” which investigated various sporting clichés. But, without the pressure from 80,000 hostile fans, officials distributed fouls, yellow cards and red cards more evenly, stripping away what had been a traditional advantage for the home team.

“I don’t think there’s any conspiracy,” he added. “I think refs are professionals, they’re trying to get it right. But they’re human.”

Moskowitz notes there are caveats. The best basketball teams are tough to beat anywhere, but the top three teams in the N.B.A. this season are a combined 49-5 at home. Three of the four teams playing at home in this weekend’s N.F.L. divisional round enter as considerable favorites.

But, across sports, securing home-field advantage for the biggest games might not be as meaningful as it once was. The last five games of the N.B.A. finals last summer were won on the road. It marked the third time in four years that the league’s championship was decided without confetti falling from the rafters. (Small sample size warning: Kevin Durant was hurt in June; the Warriors could have won on Mars in 2018, and in 2016, well, LeBron.) The last Stanley Cup champion to clinch at home? Your 2015 Chicago Blackhawks.

Advanced analytics might help the trend gain further momentum.

Konstantinos Pelechrinis, a professor of computing and information at the University of Pittsburgh, scrutinized the N.B.A.’s Last Two Minute Reports, the league’s assessment of officiating calls in the final two minutes of a close game, between 2015 and 2019. He found that incorrect calls or non-calls in the period occurred at a rate of 7.2 percent for away teams and 6.7 percent for home teams.

In other words, officials were more likely to make an incorrect call that benefits the home team in the most critical moments of a tight game. The majority of the mistakes, Pelechrinis said, were non-calls, when the referees swallowed their whistle. Exposing that data, as the league now does, is intended to help referees. Now that coaches can challenge calls in the N.B.A., Pelechrinis expects the league’s home winning percentage, which was as high as 68.5 percent in 1977 but on a downward trend for a generation, to continue sliding as it has in the N.F.L.

Employing a regression-based model to weight all teams equally, Pelechrinis found that playing at home was worth an average of 2.4 points per game in the N.F.L. between 2005 and 2018. This season, the advantage dropped to less than half a point.

“It could be a statistical anomaly,” Pelechrinis said. “It could just be the scheduling. But it was interesting.”

Gambling oddsmakers have noticed. Their formulas got thrown for a loop this season after N.F.L. home teams went 102-131-10, when the point spread is included in the calculation.

“What we’ve had to learn, on our side of the counter, is that not all home fields are in fact created equal,” said Vinny Magliulo, who ran the sports books at Caesars Palace and Wynn Las Vegas and is now the sports book director at Gaughan Gaming.

In recent years, stadiums have gotten better at adding distractions and manufacturing tension. Even the subtlest tricks can have an effect on a team’s mind-set, Cowher said, like when the Denver Broncos put a sign in the opposing locker room warning visitors of the signs of altitude sickness. But coaches have countered with more practice strategies to keep players from getting rattled, by importing crowd noise, for example.

Cowher, who went 67-59 in his career on the road, said that the best way he knew how the nullify a noxious crowd was to score early. “You get past that initial energy,” he said, “you find yourself in the second and third quarter and you know what? It’s even.”

Ken Belson contributed reporting. Photographs by NFL.com; Photo illustration by The New York Times.