All football historians know about the 1978 rules changes. Here’s an except I wrote about how those changes changed the NFL forever:

There were two key rules changes enacted in 1978. The first prohibited bumping, chucking, or otherwise making anything other than incidental contact with a receiver beyond five yards from the line of scrimmage. The second allowed offensive lineman to be able to extend their arms, and push with open hands, allowing for better blocking and fewer holding penalties. With those rules in place, quarterbacks needed fewer blockers and receivers needed to be less skilled to get open. As a result, three and four wide receiver sets become more common, and the fullback was phased out…. From 1970 to 1977, non-starting wide receivers consistently produced just under 10% of the team’s total receiving yards; by 1990, that number had doubled, and has shown no signs of subsiding.

So what was the impetus for those changes? The 1977 season, which was a passing nightmare. In 1976, teams averaged 4.07 Adjusted Net Yards per Attempt, defined as (Gross Passing Yards + 20 * TDs – 45 * INTs) divided by (Pass Attempts – Sack Yards Lost). Now a 4.07 league average ANY/A wasn’t high – the ’60s NFL saw an average ANY/A of 4.59 — but it wasn’t notably low, either. In fact, 1976 was a slightly better passing environment than the trailing five year average of 4.01. Then, 1977 happened: teams averaged just 3.55 ANY/A, the lowest mark in the NFL since 1953. This was a dramatic decline in passing production of 0.52 Adjusted Net Yards per Attempt.

Fast forward 40 years. In 2016, the league-wide ANY/A average was 6.22, a shade off of the 6.26 ANY/A average in 2015. In fact, 2014 (6.14 ANY/A), 2015 (6.26), and 2016 (6.22) are the three best passing seasons in NFL history. There was little reason to expect 2017 to be any different, but it was: the NFL average ANY/A dropped to 5.91 last season, a decline of 0.31 ANY/A. That was the single largest year-over-year decline since 1976-1977. [continue reading…]

Seven and a half years ago, I asked the question, why do teams run the ball? Today, I want to revisit that post, given that a lot has happened over the last seven and a half years.

Let’s begin my analyzing league-wide pass and rush efficiency. To measure rush efficiency, we will use Adjusted Yards per Carry, which is calculated as follows:

(Rush Yards + 11 * Rush TDs + 9 * Rush First Downs) / (Rushes)

For passing, we will use a modified version of ANY/A by also giving credit for first downs. Here’s the formula:

(Gross Pass Yards – SackYardsLost + 11 * Pass TDs + 9 * Pass First Downs – 45 * INTs) / (Pass Attempts + Sacks)

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There have been 105 teams to have at least two players gain 1,000 receiving yards in a season. It first happened in 1960 in the AFL, where wide receivers benefited by playing against lower quality of defensive backs and also a fourteen-game schedule (the NFL schedule switched from a 12 to 14 games the following year). New York’s Don Maynard led the team with 1,265 yards, while Art Powell finished with 1,167. Maynard and Powell repeated the feat in 1962, and then Maynard and the Jets’ George Sauer also joined the club in ’67 and ’68. In total, seven different AFL teams fielded a pair of 1,000 yard receivers, with Bill Groman and Charley Hennigan (1961, Houston), Warren Wells and Fred Biletnikoff (1968, Oakland) and Lance Alworth and Gary Garrison (1968, San Diego) rounding out the list.

But in the NFL, no team fielded a pair of 1,000 yard receivers in the ’60s, even with the 14-game schedule. And as professional football entered the dead ball era in the 1970s, it wasn’t until the passing rules changes and the advent of the 16-game schedule that an NFL team — in fact, three NFL teams — first fielded multiple 1,000-yard receivers.

One of my law school professors was very quirky, even by law school professor standards. His preferred examination method was multiple choice, but with a twist. After grading each exam, he would then divide the students into quarters based on their test score. He would then re-examine each question, and measure how the top quarter of students performed on each question relative to the bottom quarter. Any question that more bottom-quarter students answered correctly than top-quarter students would be thrown out, and the exam would be re-graded. As he delicately put out, ‘if the wrong students are getting the question right, and the right students are getting the question wrong, it’s a bad question.’

NFL passing records are falling for a variety of reasons these days, including rules changes and league policies that make the passing game more effective. But there’s another reason: for the first time in awhile, the right people are throwing the most passes in the league. And there’s no better example of that than Drew Brees. Since coming to the Saints in 2006, he’s ranked 1st or 2nd in pass attempts four times, and ranked in the top three in net yards per attempt four times. But even since ’06, we’ve seen the passing game evolve, as the best quarterbacks are now the most likely ones to finish near the top of the leaderboard in pass attempts. In 2010, Peyton Manning had his first 600-attempt season… when he threw 679 passes for the Colts. Tom Brady threw 611 passes last year for the 13-3 Patriots, making New England one of just three teams to threw 600 pass attempts and win 13 or more games in a season. The other two teams? The ’09 Colts and the ’11 Saints.

At various points in the history of the NFL, passing was viewed as an alternative to running, and the high-attempt game was the province of the trailing team. But times are changing in the NFL. I calculated each team’s net yards per attempt (NY/A) and total pass attempts (attempts plus sacks) for every year since 1970. Then, I measured the correlation coefficient between NY/A and pass attempts for the league for each of the last 42 seasons. The chart below shows the correlation coefficient between those two variables (NY/A and pass attempts) for the league as a whole for each year since the merger:
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Last year, Jimmy Graham broke Kellen Winslow’s record for receiving yards in a single season by a tight end. Winslow gained 1,290 yards as a second-year player in 1980 for the San Diego Chargers. Last year, Graham finished with 1,310 receiving yards in his second season, while also catching 99 passes and scoring 11 touchdowns. Graham broke Winslow’s 31-year-old record, but Graham was leapfrogged in about fifteen minutes. By the end of the last Sunday of the regular season, Rob Gronkowski had upped his total to 1,327 yards, making him the new single-season leader in receiving yards and receiving touchdowns by a tight end.

Jason Witten and Aaron Hernandez each topped 900 receiving yards in 2011, and Tony Gonzalez, Antonio Gates and Vernon Davis remain among the game’s elite at the position. It would not be difficult to argue that we’re in a golden age of tight ends. There’s no doubt that passing has increased in both quantity and quality; have tight ends been the biggest beneficiaries of that change?

I examined every season in the NFL since 1970, when the AFL and NFL merged. I then calculated the percentage of receiving yards for each team that went to its running backs, tight ends and wide receivers. The table below shows those results^[1]Some caveats: Obviously many players straddle the line across multiple positions. There are some judgment calls involved with H-Backs, tight ends turned wide receivers, running backs turned tight … Continue reading.

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