by Scott Kacsmar

Under pressure, pushing down on you, no quarterback asks for it. The Football Outsiders game charting project, in conjunction with ESPN Stats & Information, tracks pass pressure, along with many other things. We've published the results in Football Outsiders Almanac 2014 (can be purchased here). In the first of a two-part series on the impact of pressure in 2013, we look at how the quarterbacks fared.

One of the silliest statements you will hear on TV is when an analyst says "[Quarterback X] is a different guy when he's pressured." They usually pick one of the best players in the league to make it sound like they've cracked his code, but this statement can be applied to every single quarterback in the NFL. We have four years of this data and every quarterback with a qualified number of attempts has worse statistics when pressure is present.

The value-added analysis is finding out how each quarterback handled the pressure. The strange part is this fluctuates from year to year. In 2012, Andrew Luck (-80.2%) and Ben Roethlisberger (-80.7%) had the smallest declines in DVOA with pressure compared to without pressure. Makes a lot of sense, right? They are both big guys, hard to bring down and mobile enough to get out of trouble. This past season, Luck (-102.5%) fell to 15th and Roethlisberger (-111.3%) to 19th. This is a stat where most would expect Aaron Rodgers to shine as well, because he can throw with the best of them, he can do it on the run, and he can reset his feet and fire accurately. Well, after ranking 10th in "pressure drop" in 2012, Rodgers had the third-worst DVOA decline in the league when under pressure last year.

I first noticed the lack of year-to-year consistency when I started collecting general stats on "Under Pressure" splits from STATS LLC over eight years ago. Not helping matters is the fact that pressure can be a very subjective "eye of the beholder" stat to track. We have plays where we disagree with ESPN on the presence of pressure, and we suggest revisions all the time. If there's a disagreement about the amount of pressure on a 50-yard touchdown pass, that's going to skew the season stats.

So maybe it's due to the difficulties of game charting, or maybe pressure just creates a more chaotic game with bigger gains and bigger losses. Receivers break their routes, defenders lose their assignments, and you can have a wide-open receiver for a huge gain. You could also suffer a 12-yard loss on a sack. Pressure really changes the game.

The following table shows all 40 quarterbacks with at least 200 regular-season pass plays. Scrambles and Defensive Pass Interference are included, but aborted snaps are excluded. The quarterbacks are sorted by ascending frequency of pressure, and the "Difference" section is ranked from smallest to largest in terms of the drop in DVOA when under pressure.

A couple of housekeeping notes: First, sacks marked as "coverage sack" and scrambles marked as either "coverage scramble" or "hole opens up" do not count as pressure plays. Second, DVOA here is not actually passing DVOA; it is team offense DVOA with this player either passing or scrambling. The reason for that is that scrambles are counted as runs rather than passes in DVOA. That's something we plan on eventually changing, but we haven't had the opportunity yet (and of course, we'll need to figure out how to handle that on earlier seasons where scrambles were not specifically marked in the play-by-play).

Qualifying QB Plays Pct

Pressure Rk with Pass Pressure without Pass Pressure Difference Yds DVOA Rk Yds DVOA Rk Yds DVOA Rk P.Manning 688 14.8% 1 4.7 -50.8% 9 8.6 82.8% 2 -3.9 -133.7% 29 A.Dalton 645 16.4% 2 1.2 -117.8% 36 7.9 39.9% 20 -6.7 -157.7% 35 M.Stafford 671 19.4% 3 4.4 -53.3% 10 7.4 27.3% 31 -3.0 -80.6% 7 T.Brady 680 20.3% 4 2.2 -78.1% 23 7.4 55.5% 10 -5.2 -133.7% 28 M.Cassel 283 20.5% 5 2.9 -56.0% 11 7.3 7.9% 39 -4.4 -64.0% 4 A.Smith 601 21.1% 6 2.7 -76.0% 22 6.8 35.9% 21 -4.1 -111.9% 21 M.Flynn 239 21.8% 7 0.1 -182.8% 40 7.4 30.5% 28 -7.4 -213.3% 40 E.Manuel 369 22.0% 8 2.6 -70.4% 18 6.5 10.3% 38 -3.9 -80.7% 8 P.Rivers 601 22.0% 9 4.6 -32.2% 5 8.6 76.3% 4 -4.0 -108.5% 18 T.Romo 585 22.1% 10 2.5 -74.9% 21 7.4 44.2% 14 -4.9 -119.1% 25 A.Rodgers 330 22.1% 11 2.0 -104.6% 34 9.4 79.6% 3 -7.4 -184.2% 38 B.Roethlisberger 639 22.2% 12 3.8 -63.8% 15 7.3 47.5% 11 -3.6 -111.3% 19 R.Tannehill 659 22.3% 13 1.1 -131.5% 38 6.9 43.8% 15 -5.8 -175.3% 37 M.McGloin 224 22.3% 14 3.5 -73.2% 19 8.3 20.5% 33 -4.7 -93.7% 10 D.Brees 703 22.5% 15 2.9 -82.2% 24 8.5 73.1% 5 -5.6 -155.3% 34 R.Fitzpatrick 398 23.1% 16 4.9 -44.5% 7 7.0 32.9% 26 -2.1 -77.5% 6 C.Henne 556 23.7% 17 2.0 -74.2% 20 6.7 10.3% 37 -4.7 -84.5% 9 C.Newton 557 24.2% 18 2.5 -58.2% 13 7.4 43.3% 18 -4.9 -101.5% 13 J.Campbell 346 24.6% 19 4.0 -27.5% 3 6.6 14.1% 36 -2.6 -41.6% 1 S.Bradford 289 24.9% 20 2.3 -84.3% 26 7.4 28.6% 29 -5.1 -112.9% 22 Qualifying QB Plays Pct

Pressure Rk with Pass Pressure without Pass Pressure Difference Yds DVOA Rk Yds DVOA Rk Yds DVOA Rk J.Flacco 690 25.1% 21 2.2 -91.3% 29 7.0 23.7% 32 -4.8 -115.0% 23 N.Foles 366 25.7% 22 3.4 -48.5% 8 9.5 94.8% 1 -6.2 -143.4% 32 J.McCown 245 25.7% 23 5.5 8.0% 1 8.4 65.2% 7 -2.9 -57.2% 3 C.Kaepernick 507 26.0% 24 3.8 -35.7% 6 7.9 62.0% 8 -4.1 -97.7% 12 J.Cutler 386 26.2% 25 4.9 -23.8% 2 7.5 32.9% 25 -2.6 -56.8% 2 C.Palmer 632 26.6% 26 2.1 -117.8% 37 8.3 57.2% 9 -6.2 -175.0% 36 J.Locker 214 27.1% 27 3.1 -66.1% 16 7.4 40.0% 19 -4.3 -106.1% 17 A.Luck 662 27.3% 28 3.6 -58.8% 14 7.4 43.7% 17 -3.8 -102.5% 15 E.Manning 607 27.5% 29 2.1 -96.5% 30 7.6 14.9% 35 -5.5 -111.5% 20 M.Schaub 388 27.8% 30 2.4 -87.0% 28 7.1 15.4% 34 -4.7 -102.5% 14 B.Weeden 301 27.9% 31 0.9 -160.6% 39 7.0 28.4% 30 -6.2 -189.0% 39 R.Griffin 533 28.0% 32 3.0 -86.9% 27 7.2 31.0% 27 -4.2 -117.9% 24 C.Ponder 296 28.4% 33 2.4 -97.8% 31 7.6 33.2% 24 -5.2 -131.0% 27 K.Clemens 274 28.5% 34 2.8 -101.0% 33 7.1 46.0% 13 -4.2 -147.0% 33 M.Ryan 712 28.7% 35 3.2 -57.2% 12 7.4 46.4% 12 -4.3 -103.6% 16 G.Smith 521 29.0% 36 2.2 -108.3% 35 7.5 33.6% 23 -5.2 -141.9% 31 M.Glennon 480 31.7% 37 1.5 -83.7% 25 7.0 43.8% 16 -5.5 -127.5% 26 T.Pryor 338 34.3% 38 2.4 -67.4% 17 7.2 7.3% 40 -4.8 -74.7% 5 R.Wilson 508 36.6% 39 4.9 -27.6% 4 8.5 67.3% 6 -3.6 -94.9% 11 C.Keenum 276 37.7% 40 2.1 -99.6% 32 8.1 35.3% 22 -6.0 -134.9% 30 NFL 475.0 25.2% -- 2.9 -76.1% -- 7.6 40.7% -- -4.7 -116.8% --

Note: This table appears as "2013 Quarterbacks with and without Pass Pressure" in the Statistical Appendix of FOA 2014, but the DVOA numbers are incorrect. In the original version of the book, this table accidentally used the DVOA version with offense as the opponent adjustment instead of defense. The correct numbers are posted above here, and those of you who have purchased the book in PDF form can now download a corrected version, free of charge. We apologize for any inconvenience.

The teams who used multiple quarterbacks are always fun to study, but they really stand out here. Jason Campbell actually had the smallest pressure drop for DVOA (-41.6%) in the last four seasons. He's the third unspectacular quarterback to lead the league after Shaun Hill (2010; -42.4%) and Josh Freeman (2011; -65.3%). Campbell somehow ranked third with pressure and was the fifth lowest without pressure. Brandon Weeden had a much different experience behind Cleveland's offensive line. He was the second worst with pressure and still well below average without.

If you don't pressure Aaron Rodgers, there's really no hope for your defense. He ranked third in DVOA without pressure, but fell to 34th with pressure, including a broken collarbone on a sack against the Bears. That eventually led to the return of Matt Flynn in Green Bay, and no one fared worse against pressure. Rodgers and Flynn had nearly identical pressure rates and both averaged 7.4 fewer yards per play under pressure -- the highest declines in the league.

Marc Trestman's Chicago Bears may have the most mystifying results of any 2013 offense. Josh McCown had the highest DVOA (8.0%) with pressure. He's the only qualified quarterback in the last four years with a positive DVOA under pressure. Jay Cutler finished a respectable second, but the difference really came without pressure. Cutler fell to 25th while McCown was still strong at seventh. I'm certainly not going to say McCown will carry this success to Tampa Bay, but he made one of the best plays last year under pressure: a touchdown pass to Brandon Marshall on third down in the first quarter of the Week 9 win over Green Bay.

Inexperienced passers Terrelle Pryor and Case Keenum were two of the three most pressured quarterbacks, but they brought a lot of that on themselves. Notice that Matt Schaub had a pressure rate nearly 10 percentage points lower than Keenum, and Matt McGloin was 12 percentage points lower than Pryor. Those were the two biggest pressure rate differences among our eight teams with multiple quarterbacks. The third biggest was Minnesota with Matt Cassel handling pressure much better than Christian Ponder. However, only Pryor had a lower DVOA without pressure than Cassel. Realistically, how long can the Vikings go without giving the keys to Teddy Bridgewater?

I've noticed a lot of negative talk this week about Buffalo's EJ Manuel. As a rookie, he had the third-lowest DVOA without pressure (10.3%). Granted, our data only goes back to 2010, but this is a very discouraging sign. We have 40 examples where a quarterback had a DVOA without pressure under 20.0%. Not one of those quarterbacks was a good starter after that point. Now Eli Manning (14.9% in 2013) has a great shot to rebound, but where he's at entering his 11th season is way beyond where Manuel is at. Matt Schaub (15.4% in DVOA) might get back on track in Oakland, but who would want to bet on that? As for Sam Bradford, let's just say we're still waiting to see a good quarterback there. It's not a good sign if your quarterback's not taking advantage of adequate protection. Even Thad Lewis (not enough attempts to rank) had a 31.5% DVOA without pressure in Buffalo last year. However, that leaves Lewis with the biggest pressure drop (-232.0%) in four years. Buffalo has some issues at quarterback. What else is new?

Robert Griffin III (27th) and Matt Ryan (12th) were the only quarterbacks to have the same rank in DVOA with and without pressure. Some may have expected Ryan Tannehill to have a huge difference in his rankings, and to some extent, he did. Few would have expected his ranking of 13th in pressure rate. Yes, Tannehill faced a below-average amount of pressure in 2013. Tannehill's problem was that pressure really made him struggle, ranking 38th in DVOA. He was much more respectable without pressure at 15th, but he has to handle pressure better. Most of his league-leading 58 sacks were on the offensive line, but he still suffered the fourth-biggest pressure drop in the league. The split was a little similar in his rookie year when he ranked an unimpressive 26th in pressure drop.

Philip Rivers was dead last in pressure drop (-211.2%) in 2012. Mike McCoy and Ken Whisenhunt put better blocking in front of him, got the ball out of his hands faster, and Rivers moved up to 18th in pressure drop last year. Rivers is another intriguing case, because he has two of the top 12 seasons since 2010 for DVOA with pressure (2010 and 2013). Rivers (two) and Roethlisberger (three) are the only quarterbacks with multiple seasons in the top 25 for DVOA with pressure. In 2013, Rivers was one of six quarterbacks to rank in the top 10 for DVOA with and without pressure (the others being Nick Foles, Peyton Manning, Russell Wilson, Josh McCown and Colin Kaepernick).

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Generally, the best quarterbacks in the league will play like the best quarterbacks if you don't get pressure on them. Last year, that familiar group of Peyton (second), Rodgers (third), Brees (fifth) and Brady (10th) all ranked in the top 10 in DVOA without pressure. What about other veterans? I used everyone with at least three qualified seasons (minimum 200 plays) since 2010 and ran a few year-to-year correlation tests. Peyton and Chad Henne are missing 2011 in their data, but that's okay since they're actually two of the most consistent quarterbacks (just in opposite directions of success). Our sample contains 97 seasons by 27 quarterbacks, so it's not the most statistically sound test, but it's a solid start.

Stat Correlation coefficient Pressure rate 0.44 DVOA with pressure 0.18 DVOA without pressure 0.58 Pressure drop 0.02

Similar to studies on sacks, we see that quarterbacks have a considerable impact on controlling how much pressure they face. If you're getting rid of the ball quickly, then it's hard for the defense to get that close. Dance around and even the best offensive linemen will struggle to hold their blocks. We know linemen come and go, so pressure rate's 0.44 correlation is a solid indicator of the quarterback's impact. The 0.58 correlation for DVOA without pressure is even better. Quarterbacks can play at a fairly consistent level each year when the element of pressure is gone and it's just a matter of making reads and throws. Add pressure, and you're going to get a lot of variation in performance, hence low correlation (0.18). Even if you're a great quarterback, it's almost impossible to sustain a high level of play under pressure.

That's why we remember the highlights best (or lowlights for players perceived to be bad under pressure). That's why I'm still in awe over McCown's touchdown pass in Green Bay, but struggle to remember similar plays from him last year. The successes are rare. Would McCown have a positive DVOA under pressure if he played a full season instead of 245 plays? Our data suggests he wouldn't, but the great part is that we actually have this data now, and will continue it for each season going forward.

Unsurprisingly, pressure drop had a very small, albeit non-zero correlation (0.02). Pressure's randomizing effect on quarterback performance makes it too hard to expect a consistent difference between plays with and without pressure.

Quarterbacks are only getting pressured on about a quarter of all dropbacks, but those are the plays that can really make the difference in the game. Get a third-down stop here, or force a pick there. Pressure is a defense's best weapon.

Nothing represented this better in 2013 than the Denver Broncos and Seattle Seahawks. Peyton Manning had the lowest pressure rate in the league for the second year in a row. Seattle's offense had the worst pressure rate with Russell Wilson ranking 39th individually. Yet in Super Bowl XLVIII, Wilson was not sacked or even hit once. Manning trailed 15-0 after throwing one incompletion, which was a bad interception after Cliff Avril brought some pressure from the edge. Manning's second interception was also caused by Avril, who hit the quarterback as he threw. The ball hung in the air and Malcolm Smith returned it 69 yards for a touchdown.

Denver trailed 22-0, the game was practically over, and the MVP quarterback had thrown only two incompletions of consequence. Both were the result of third-down pressure. Seattle may not have protected its quarterback well for the first 18 games of the season, but it also had the league's best defense at putting pressure on the opposing quarterback. Two plays were all Seattle needed to embarrass a record-setting offense. Of course, Denver only needed the opening snap to embarrass itself, but the super blowout was paced by a couple of pass pressures.

In part two later this week, we'll look at Seattle and the other 31 defenses' success with and without pass pressure.