This is an interesting concept.

The adjusted leaderboards for single season and all time are images in the article.

https://sports.yahoo.com/the-real-nfl-passing-yardage-leaderboards-173905994.html

Yahoo Sports
The ‘real’ NFL passing yardage leaderboards
Henry Bushnell
Henry Bushnell
November 11, 2020·9 min read

Barring something catastrophic, on Thursday night in Tennessee, Philip Rivers will step into an exclusive club. With his first or second completion of a prime-time showdown between the Indianapolis Colts and Titans, he’ll leapfrog Dan Marino on the NFL’s all-time passing yardage leaderboard. He’ll ascend into fifth place, barring the 20th century from the top five forever. And he’ll help tell a story.

Marino retired after the 1999 season atop that list and many others. He was widely regarded as the NFL’s quarterbacking GOAT. But since, countless records have fallen. Active quarterbacks touched two others on Sunday. Rivers will be the third to equal or top a Marino mark this week. And he isn’t alone flooding record books at startling heights. Last month, Joe Flacco passed Johnny Unitas on this same career passing leaderboard. This month, Flacco passed Joe Montana.

The upended leaderboards tell two stories actually. One is about an unparalleled generation of quarterbacks. The other is about the game they’ve played – which is different than the game Marino played, which was different than the game Unitas played. Marino, in his day, was better than Rivers in his day. Unitas in his day was worlds better than Flacco in his. Few, if any, would argue otherwise.

There are, however, few stats that recognize old-time greatness anymore. As Joe Namath says, “the game has evolved.” Jameis Winston, Matthew Stafford and Kirk Cousins have each thrown for more yards in a single season than Unitas, Montana or Brett Favre ever did. Wondrous feats are being washed away by a rising tide. They’re preserved only by grainy footage and memory. Numbers have lost historical meaning.

That is, until we whipped up a spreadsheet. Recalled some Econ 101. And designed a system that contextualizes all of them.

Welcome to inflation-adjusted passing yards, where Winston’s 2019 season ranks 41st instead of eighth all-time. Where Drew Brees and Tom Brady are no less remarkable, but where Unitas gets his due. Where Namath’s 1967 masterclass is the most prolific passing season ever, and Marino’s 1984 campaign is close behind.
(Albert Corona/Yahoo Sports illustration)
(Albert Corona/Yahoo Sports illustration)

Using Pro Football Reference data, Yahoo Sports created an index that puts every NFL passing yard dating back to 1948 in 2019 terms. Think of a Consumer Price Index, but for football statistics. The goal was to compare quarterbacks not directly to their successors or predecessors, who played a fundamentally different sport; but rather indirectly via comparisons to their contemporaries. To do this, we used yearly leaguewide averages to calculate passing yardage inflation rates dating back 70-plus years. We found, for example, that 1 passing yard in 2004 is worth 1.16 yards in 2019; that 100 passing yards in 1973 is the equivalent of roughly 175 yards today.

We then used this index to reconfigure the NFL’s leaderboards. The results – the “real” leaderboards, as opposed to the “nominal” ones – are a far more accurate representation of quarterbacking greatness throughout NFL history.
The Real Career Passing Leaders

We focused on two traditional lists: The NFL’s career passing leaders, and best single seasons. When adjusted for inflation, one list changes modestly. The other, however, looks unrecognizable.

The career leaderboard holds relatively steady. Active stars, as you’d expect, slide down a bit. Rivers drops out of the top five. Matt Ryan falls out of the top 10. Aaron Rodgers sinks from 12th to 19th.

Old-timers, meanwhile, rise. Fran Tarkenton, who played from 1961-78, leapfrogs modern gunslingers, from 13th up into fifth. His 47,003 yards prior to the passing boom are worth 72,999 today. Unitas, who dazzled in even more ancient times, jumps from 22nd to eighth. Y.A. Tittle, who retired pre-merger, rises from 38th to 14th. (We extended our data back to 1948, Tittle’s first season.)
(Albert Corona/Yahoo Sports illustration)
(Albert Corona/Yahoo Sports illustration)

But the greats are still the greats. Brees and Brady still sit atop the “real” leaderboard. Brady, a couple weeks ago, passed Favre, who keeps Peyton Manning out of the adjusted top three. All have certainly benefited from the rule changes, scientific advancements and offensive innovations that our index accounts for. They nonetheless tower above their peers, even more so than Marino, Tarkenton and Unitas towered above theirs.
The best inflation-adjusted seasons ever

The full force of football’s evolution has ravaged a different leaderboard. Of the top 25 individual passing seasons on record, 24 come from the 21st century. Winston, Stafford, Cousins and Tony Romo are present. Dozens of Hall of Famers, conversely, are nowhere to be found. This is why contextualizing numbers is necessary. This is why adjusting for inflation paints a more useful picture of single-season stardom.

When we do, the top 10 gets a makeover. Truly exceptional passing campaigns spring to the top. Names like Joe Namath, Warren Moon and Dan Fouts appear.

Namath, in 1967, threw for 286 yards per game in a league that averaged just 200. His 4,007 yards that year, in 14 AFL games, are the equivalent of 5,592 yards in 16 games today – the most real single-season yards ever.

Brees’ 5,476 yards in 2011 – which stood as the nominal record for two years – maintain their spot at No. 2. Dan Marino’s 1984 wizardry rises from No. 9 to No. 3. Fouts cracks the top 10 twice – and would a third time if we counted his strike-shortened nine-game season in 1982. Projected over 16 games, his 2,883 yards that year equate to 5,869 real yards today.

His aerial assault on NFL defenses from 1979-82 was, in real terms, the best four-year stretch in league history. Those Chargers passing attacks, Fouts says, “paved the way for the way the game is played today.”
Going back to 1967

Namath still remembers the final quarter of his record-setting season. But not because he gunned down the record on a late drive. “Henry, we didn't even know about it ‘til after the game,” he swears.

Instead, he remembers looking across the field at the Chargers’ sideline. Chargers QB John Hadl was waving a white towel. Namath got the memo. His Jets, up three scores, didn’t throw the ball the rest of the afternoon. Namath’s reasoning: “Let's get out of the season all healthy.”

Even without some late stat-hunting, however, Namath’s 4,007 yards were otherworldly at the time. No other quarterback ever cracked 4,000 in a 14-game season. The mark stood for 12 years, until schedules expanded, because the sport wasn’t designed for well-oiled passing machines. The Jets, Namath says, had a grand total of two offensive coaches. Player salaries were five figures. Some teammates would work normal jobs – selling insurance, painting houses, trading stocks – before arriving for practice at noon. Offseason conditioning was limited. Friday surveys to choose pregame meals were emblematic of 1960s dietary regimens.

“Weeb Ewbank, our head coach, would stand up in front of us with a pencil and paper,” Namath recalls. “He'd say, ‘Alright, now for breakfast, how many guys want pancakes?’ And the hands would go up. ‘Alright, how many guys want eggs?’ And the hands would go up. We knew nothing about nutrition.”

They also played by inhibitive rules. Cornerbacks could maul receivers without consequence. Linebackers could take aim at quarterbacks without fear of flags. The unchecked physicality helped defenses, and helps explain why 1 passing yard in 1967 is, per our inflation index, worth 1.3 yards today (and 1.49 yards when we project a 14-game season out over 16 games).
KANSAS CITY, MO - NOVEMBER 5: Ernie Ladd #99 of the Kansas City Chiefs rushes quarterback Joe Namath #12 of the New York Jets during an NFL football game at Kansas City Municipal Stadium November 5, 1967 in Kansas City, Missouri. Ladd played for the Chiefs from 1967-68. (Photo by Focus on Sport/Getty Images)
When adjusted for inflation, Joe Namath threw for more yards in 1967 season than any quarterback in NFL history. (Focus on Sport/Getty Images)
How rule changes changed the game

The passing game’s historical inflection point arrived in 1978. That’s when the NFL adopted, among other amendments, the “Mel Blount rule,” colloquially named after the Hall of Fame corner notorious for his physical play. The rule outlawed much of that physicality, and unshackled downfield offense. Linemen were also given permission to pass-block using extended arms and open hands. As coaches realized, at varying speeds, what the rules had unleashed, passing yardage soared, from 162 yards per team per game in 1977 to 223 yards four years later.

For the better part of three decades thereafter, the numbers stayed in that ballpark. This is why inflation adjustments don’t send Marino, Moon and John Elway hurtling up the career leaderboard. Every year-to-present inflation multiplier from 1983 to 2008 is between 1.11 and 1.21.

The second boom didn’t begin until roughly 2009. Rule changes were again catalysts. The NFL increased protections for “defenseless receivers” and QBs, which encouraged the adoption of pass-happy spread offenses. The most prolific passing season ever is 2015, and 2020 could top it. Everybody, across the board, now passes more, and more efficiently, than ever.

The trend explains why the likes of Ben Roethlisberger, Ryan, Rodgers and even Stafford should also pass Marino sometime this decade. And it’s why we took on this project. The point isn’t that a player like Tarkenton or Unitas was, in a vacuum, better than Ryan or Stafford. “These guys, they throw that ball so much better than we did back then,” Namath says. “They practice so much more. They're physically stronger.” The point, rather, is to compare each against the standard of his own time, against peers who operated under the same rules and norms, with the same resources at their disposal.

The nominal stats don’t do this, which is why they don’t mean what some want them to mean. Ryan’s numbers, for example, will be used to bolster his Hall of Fame case. But if the baseline continues inflating while the standards remain stale, the Hall will overflow. The historical comparisons are borderline useless.

Unless, that is, you adjust for inflation. The numbers spell out what Fouts suspected: That, if those prolific Chargers offenses led by coach Don Coryell were transported to the present, “we'd be among the leaders, there's no question.”

Fouts wasn’t surprised when I told him of his inflation-adjusted standing. Instead, he used it to make a case of his own: That Coryell, who pioneered the vertical passing game, should be right alongside him in the Hall.

“Send those numbers to each Hall of Fame voter,” Fouts said.

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