Alex Smith takes a lot of heat for not being able to throw the ball vertically downfield. Or, at least, he takes a lot of heat for not throwing the ball down the field very frequently.

But is it warranted?

I mean, think of this intuitively. If a team gains 10 yards on a play where the ball traveled 10 yards through the air to a receiver, is it any different than a team running a 1-yard bubble screen that features 9 yards after the catch? If a short slant pattern creates 32 yards after the catch was made, is it any different than a touch pass down the sideline that goes the same distance?

From a production standpoint, no. The answer to both of those questions is no.

Passing plays aren't that simple, though. And when you take a deeper look at quarterbacks who can get some loft on the ball, it becomes pretty clear: air yards matter.

Measuring Production

If you're new to numberFire, then you're more than likely unaware of our Net Expected Points (NEP) metric. In essence, it's our way of showing what actually happens on a football field -- how a player performs versus expectation -- as opposed to just looking at traditional statistics like yards and touchdowns. Because not all plays that go for the same yardage are created equally: a 10-yard gain on 3rd-and-12 means a lot less than a 10-yard gain on 3rd-and-9.

For more on Net Expected Points, check out our Derek Anderson as the top air yards per attempt leader despite barely playing football in 2016.

But you can see how this is different -- and more accurate -- than the original table. Instead of looking at all of the yards, we're looking at them on a per-attempt basis. It equalizes the sample.

So back to the original question: how do air yards impact quarterback performance?

Air Yards and Quarterback Performance

Because we've got our nifty Net Expected Points metric, the rest of this is pretty straightforward. The chart below depicts air yards per attempt versus Passing NEP per drop back averages for all 100-plus attempt quarterbacks since 2011, the year the quarterback position became broken in the NFL.

See any correlation?

You should.

What this is showing is that there's a relatively strong connection between how far a quarterback is throwing the ball per attempt and how many actual points he's producing for his team with each drop back. And keep in mind, Passing NEP per drop back includes sacks, too.

You'd think a passer getting more air under the ball would have a higher chance to be sacked given the time needed in the pocket (this isn't tested, just a hypothesis), so this just enforces the idea that air yards do, indeed, matter.

There are naturally going to be exceptions to the rule, which is why the r-value here is closer to 0.60 rather than 1. Tom Brady's a great outlier example: of the 252 quarterbacks in the sample, Brady's best air yards per attempt season ranked 64th. In fact, in 2013, his air yards per attempt was just 3.49, or the 178th-highest rate in the cohort. Meanwhile, we know Brady is a great passer who's always ranked in the top-five in Passing NEP per drop back.

Maybe this just plays into his brilliance. Maybe Tom Brady is so good because getting consistent production through yards after the catch is difficult, but he knows how to maximize that aspect of the game.

And, look, a lot of this data isn't even necessarily skill-based. A quarterback may be in an offensive system that calls for short passes. Or maybe the signal-caller just doesn't have time to throw the ball downfield with any sort of frequency.

But what we do know is that throwing the ball down the field does matter. Air yards really are important.