Kyle Allen and Patrick Mahomes are at opposite ends of the quarterback spectrum. Allen was an undrafted free agent; Mahomes is one of the most talented quarterbacks in league history and was the 2018 NFL MVP.

Allen ranks 32nd out of 34 qualifying quarterbacks in the most basic (in a good way) of passing stats: net yards per attempt.

Mahomes ranks 1st this year in NY/A, after ranking 1st in the same stat last year among quarterbacks who started at least 8 games.  Net yards per attempt is a good stat, and Mahomes is excellent at it because he’s an excellent quarterback (or maybe vice versa).

But you know better than to expect this to be a “Mahomes good Allen bad” post. Because I did a triple take this morning when I noticed that Kyle Allen has thrown for first downs at a higher rate this season than Mahomes.  That seemed impossible, and I had to double check twice just to make sure the data wasn’t wrong.

In general, there is a significant correlation between Net Yards per Attempt (which is passing yards, net of sack yards lost, divided by pass attempts plus sacks) and Passing 1st Down Rate (which is passing first downs divided by pass attempts plus sacks).   Both of these are very good stats to measure quarterback play, and last year, Mahomes led the NFL with a 43.2% passing first down rate.   Passing 1st Down Percentage is a good quick and dirty stat, and one where the best quarterbacks tend to fare very well. It is certainly not biased against a player like Mahomes.  But this year, Mahomes ranks 13th in that metric despite still having a very good NY/A average, while Allen shockingly ranks 11th in the metric.

So we have two pretty good, and easy to calculate passing stats, that in general are very correlated.  How correlated? Take a look at the graph below, which shows the same data as the table above.  And while the logos are for teams, the data  is for individual quarterbacks, not team-level data. So the Jets logo is only Sam Darnold, not the full Jets passing stats in 2019. And for the Redskins, Titans, and Steelers, it’s Dwayne Haskins, Ryan Tannehill, and Mason Rudolph in the chart below.  The Panthers, and to a lesser extent, the Chiefs, stand out as a notable outlier: [continue reading…]