The Eagles will host the Seattle Seahawks on Sunday in the final game of the NFL’s wild-card playoff weekend. Because the Birds won the NFC East, they get to enjoy the comforts of home despite winning two fewer games than Seattle.

Teams put a lot of effort into earning home-field advantage. The Seahawks should know: They played a hard-fought contest against the San Francisco 49ers on Sunday with a chance to host a playoff game on the line and came up inches short. San Francisco has home-field advantage for as long as it’s alive in the NFC; Seattle is unlikely to get a home date this postseason.

But there’s a dirty little secret about home-field advantage this NFL season: Excluding international games, home teams had their worst record in 47 years and were outscored for the first time since at least the 1970 AFL-NFL merger.

Those are facts the Seahawks should also know, because they’ve lived them. Seattle went 95-41 in the regular season at CenturyLink Field from its opening in 2002 through 2018, but was 4-4 there this year and was outscored 229-205.

The Eagles followed a more traditional path to their 9-7 mark. They were 5-3 at Lincoln Financial Field, where they outscored their foes by 168-134, and they were 4-4 on the road, getting outscored, 220-217.

Is this a blip or a trend? This season might turn out to be the nadir, but looking at winning percentage, points scored, and yards gained, there is evidence that home-field advantage in the NFL hit its peak in the 1990s and has since been on a decline.

(All statistics and graphics do not include games that were played at a neutral site or ended in a tie.)

Not-so-sweet home

Across the league, home teams won just 52% of their games this year, the lowest since they won 50.85% in 1972. Since the merger 50 seasons ago, home teams have won 57.7% of their games. Home-field winning percentage has been in decline since it hit its peak in the late 1990s. Home teams won at least 60% of their games each year from 1995 to ’99. Outside of that span, they have never put together even two straight years with that high of a success rate.

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Missing the points

Since the merger, road teams had never outscored home teams until 2019, when hosts scored 0.21% fewer points than their visitors. A year-by-year look at the percentage difference in points scored by home teams compared to road teams shows it’s never come close to happening before. The difference in favor of home teams crossed 18% eight times between 1973 and 2005. It has crossed 16% just once since then.

Measuring with a yardstick

Home teams had a bad year measured by percentage difference in yardage gained as well, putting up only 1.34% more yards than road teams, their second-worst performance since 1970. Only once, in 1987, did visiting teams outgain their hosts.

Rolling with it

Looking at 10-year rolling averages in the three statistical categories gives us a longer view of what’s happening, and two of the stats point to 2019 being more than an anomaly. The winning percentage in each span from the 1987-96 period to the 1998-2007 period was higher than any other 10-year span since the merger. Five of the six worst 10-year periods, and six of the nine worst, have started since 2004.

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Scoring slump

A similar trend shows up in points scored, measured in 10-year spans. Home teams in the 1970s outscored road teams by 17.15%, the best mark since the merger. The numbers drop off steadily from that point, aside from a slight rebound in the 1990s.

Staying steady

The only statistical category that points to this era of the NFL being relatively stable for home teams is yardage. After home teams enjoyed a 5% to 6.5% advantage for the first few 10-year periods since the merger, it has generally stayed between 4% and 5% since.

Cashing in?

Even gambling experts were befuddled by home teams this year. The winning percentage against the point spread for home teams, home favorites, and home underdogs was worse this season than in any other this decade, according to gambling website

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When it matters most

What does all of this mean for the playoffs? There are fewer games from which to draw conclusions, but even with that small-sample-size caveat, all three statistics, measured in 10-year rolling spans, show similar results as the regular season: Home teams were more dominant in the 1990s than they have been lately. (Click on a category — winning percentage, points, or yards — to see the results for that category. These results consider only games since the league expanded the postseason to 12 teams in 1990.)

What does it mean?

Not much when it comes to Sunday’s Eagles-Seahawks tilt; the players and coaches will have more to do with who wins this individual game than a few broad trend lines that show home-team dominance is slipping.

But it might be influencing the gambling community. The Eagles opened briefly as a one-point home favorite, but have been a one- to two-point underdog for most of the week.

A home underdog in the playoffs? That’s yet another situation Seattle and its fans should be familiar with. Nine years ago, the Seahawks won the NFC West with a 7-9 record and hosted the 11-5 New Orleans Saints on wild-card weekend. That’s when Marshawn Lynch unleashed the Beast Quake.

Heavy underdogs, the Seahawks came away with a 41-36 win. It’s a scenario the Eagles would like to see repeat itself on Sunday.