Over the past few weeks, I've seen an interesting discussion on Twitter and various other places. People call sacks from defensive ends overrated, overvalued, etc. etc. saying that they'd rather look for people with QB hits, pressures, etc.
So here's a few reasons why sacks do, indeed, tell a story.
1) All these other stats are a real pain in the arse to find.
Ease of access in this day and age should be determined by how quickly you can find information based on a Google search. That's what Google is for: searching for stuff. So when I type in something like "QB Pressures stats 2012" and everything and their brother that comes up is offensive line and QB stuff, something isn't right.
The only solution I saw was that there's a way to download NFL game books (or stat sheets, or something) from the NFL. That is an individual game thing, and that is an incredible time sink.
2) Pressures and hurries are opinion stats.
Much like tackles, pressures and hurries are not completely accurate, unless the source has accounted for plays that were designed to be quick-release passes in spite of pressure in the face, which isn't likely.
What constitutes a QB pressure? What constitutes a "hurry"? I'd be willing to bet you'd get a bunch of different definitions depending on who you ask. PFF defines a "pressure" as "any hit, hurry, or sack".
Would Football Outsiders define it the same way? Does the NFL use that same definition?
3) Pressures don't guarantee anything.
While PFF offers this nice article comparing throws with pressure and no pressure, it still supports my side as well.
When sacked, what is a QB's accuracy? Zero.
A QB's completion percentage? Zero.
QB Rating? Like 30. Might as well be zero.
Case in point, look at our own Matty Ice in that article. He was the fifth most "pressured" QB according to PFF, but he also had a 65% accuracy, which I can't say I know the difference between that and completion percentage. Maybe if Matty hit Gonzo in the rear because he was hurried, that counts.
For instance, this play here. How many "pressures" happened on this play? Three? Four? What was the outcome?
Pressures don't do diddly doo-dah to mobile QBs. You get a "pressure", they run away. Sacks guarantee that the slippery bum isn't going anywhere.
4) Pressures do little to a good passing QB, also.
While people will point to the Denver game or perhaps even the Saints game where we ruined Brees's streak as examples for how pressures work, but I can also say that 3 of our 39 sacks came against Denver, and in our two games against Brees we had 18 passes defended, not to mention 6 interceptions.
Surprisingly, the Manning brothers were the only two really good QBs to be above average (in terms of bad) in terms of interception percentage. Eli's kinda overrated and Peyton gets a pass because neck surgeries.
4) Sacks are exponential in their effect.
Save for causing turnovers, a sack is the rarest thing you'll see from a DE. A sack not only causes a loss of down, but more often than not, it causes a severe loss of yardage. A severe loss of yardage then requires a playcalling change, at the very worst, or perhaps even a change of possession after third down.
A sack on 1st and 10 can lead to 2nd and 15, compared to 2nd and 10 on a throwaway from a pressure, or worse, a whole new set of downs.
While pressures, on average, may make a QB worse, pressures, as defined by PFF, include sacks, which are when a QB does and gets nothing. Not including those, in my best estimation, would put a slight damper on their math and comparison between pressure and no pressure.
How many times have we watched "almost got there" turn into "30 yard pass"? Happens far too much for my taste, and while PFF's article suggests there's a noticeable difference, things aren't always what they seem.
Sacks are the only definite thing on a defense, save for turnovers. Sacks mean a loss of down, a loss of yardage, and a forced change of plan for the offense.
What does pressure mean? In many cases, nothing.