The least-concentrated aerial attack in 2019 was the Colts, and you can see that breakdown here.  On average, the 32 teams had a concentration index of 15.3%, or 0.153.  In the abstract, that doesn’t mean much, but what if we calculate the average concentration index for the NFL (and AFL) for each season since 1950?

The two lowest seasons were 2018 (14.8%) and 2017 (14.9%), with 2019 and 1983 right behind those years. ^[1]Note that I excluded the 1987 season, which featured replacement players and therefore skewed the results; technically, the CC Index for the NFL that season was 12.9%.  This means that teams are spreading the ball around much more than they used to, which is a noteworthy if unsurprising result.

It also explains why passing numbers have exploded but receiving numbers have not quite kept up in recent years.  I looked at the top 10 leaders in receiving yards in each NFL season since 1950, and plotted that average in blue in the graph below against the Left Y-Axis.  I also calculated the average gross passing yards for the top 10 passing offenses in each NFL season, and plotted that in red against the Right Y-Axis.  While there is normally a close correlation, you can see that in recent years, the blue line is below the red one.  Meanwhile, in 1995, the top receivers had astronomical seasons, while gross passing numbers were not out of line with historical numbers.What stands out to you?  Please leave your thoughts and follow-up requests in the comments below.

Regular readers know that I like to calculate something called the Concentration Index for passing offenses: it’s relatively simple to calculate, and it measures how concentrated a team’s passing offense is among a small or large number of players.  To calculate, you simple take each player’s receiving yards, divide that by his team’s total receiving yards, square that result, and then add that number for each player on the offense.  For the Saints, Thomas is at 38.9%; the square of that is 15.2%, so that’s the number we use.  Jared Cook was second on the team with 705 yards, or 15.9% of the team’s receiving yards; the square of that number is 2.5%.  Do this for every player, and the Saints have a total Concentration Index of 21.1%… which is highly concentrated.

Indianapolis was the team with the least concentrated offense in the league.  Zach Pascal went undrafted in 2017, but somehow wound up leading Jacoby Brissett’s Colts in receiving yards in 2019.  He had 18.3% of the team’s receiving yards, followed closely by T.Y. Hilton at 15.1% (in 10 games), Jack Doyle at 13.5%, and Eric Ebron at 11.3% (in 11 games).  Even RB Nyheim Hines hit nearly 10%.  This is why the Colts passing offense was the least concentrated in the NFL, at just 11.1% total.

Here is where each offense ranked in this metric in 2019:

For Brissett, the 2019 season was underwhelming: he started the year hot, but declined in particular once Wayne was out. That said, he had a low sack rate and a low interception rate and led a run-heavy offense: the set of targets was underwhelming, and perhaps this study helps deflect some of the criticism for his performance.

In Arizona, rookie Kyler Murray made do without relying too much on any one player: Larry Fitzgerald had “only” 21.8% of Arizona’s receiving yards, and Christian Kirk was second with 18.7%; nobody else was above 10%. The Giants, a year after trading Odell Beckham Jr., saw Darius Slayton lead the team in receiving yards. But his 18.2% share of New York’s receiving pie was the lowest of any leading receiver in the league.

What stands out to you?