Quarterbacks vs. Defensive Personnel Packages

About a month ago, I posted an examination of running back yards-per-carry based on defensive personnel packages. In that piece, I looked at backs whose performance was boosted or hindered as a result of the opposition’s personnel choices.

Today, I’m going to make the switch from running backs to quarterbacks. Similar to our first article, we’ll examine how often quarterbacks are seeing each package, how well they’re performing in each scenario, and determine whether or not the different personnel packages have much of an impact on productivity.

To make it simple, this piece will not differentiate between, for example, 4-3 and 3-4. I’ll be creating splits based on the number of defensive backs on the field.  For example, base defense vs. nickel vs. dime.

To better explain, check out our first chart:

Shown here is a five-year trend of defensive back usage. Note the final column, which tells us that defenses had five or more defensive backs on the field on 57 percent of all called pass plays in 2008. That figure has progressively increased over the last five years, reaching a high of 67.4 percent in 2012.

As interesting as that spike is, take a look at where it’s coming from. Dime (6 DBs) has remained relatively consistent over the last five years, reaching as high as 19 percent, but never dropping lower than 15 percent. The change has come from a drop in base and an increase in nickel. NFL offenses are calling pass more often, but not at the rate defenses are utilizing more nickel.

Now that we have some perspective on league average, I can focus on individual 2012 quarterback numbers.

Shown here are the quarterbacks who had the unfortunate task of taking on a ton of nickel and dime defenses last season.

Of 39 quarterbacks with 100 or more drop backs, Peyton Manning faced five or more defensive backs on an NFL-high 85 percent of the time Denver called pass. We also see Tom Brady third on the list. Considering that Denver and New England ranked as the league’s ninth and 13th run-heaviest teams, respectively, the high number of defensive backs they faced truly shows the respect they receive from opposing defenses. Brady faced nickel an NFL-high 73 percent of the time.

The Packers (Aaron Rodgers) and Lions (Matt Stafford) make a lot of sense here, as both teams called a lot of passes and had underwhelming running games. No qualified quarterback faced the dime more than John Skelton (39 percent). As bad as the Cardinals passing game was, defenses weren’t afraid of their rushing attack either. Additionally, Arizona’s backs faced a ton of base defense, which means the offensive play-calling was very predictable. Struggles on first down are a big part as to why.

Next, we have the quarterbacks who faced five-plus defensive backs on the lowest percentage of their dropbacks.

The two 49ers quarterbacks should jump right off the page. Colin Kaepernick and Alex Smith benefited greatly from a strong defense, coupled with an effective run-heavy offensive attack. No one saw more base (59 percent) or less nickel (29 percent) than Kaepernick.

Eight of the 10 quarterbacks on our list worked in one of the league’s eight run-heaviest offenses, which certainly helps explain why they were able to benefit from fewer defensive backs when throwing the ball. The two exceptions were Brandon Weeden and Carson Palmer, which, after rough seasons, makes both look even worse than they already did.

Now that we’ve established how often quarterbacks are seeing each package of defensive backs, we can focus on performance.

We’ll kick off by looking at league average marks:

Shown is the league-wide number of drop backs vs. each package during the last five seasons. The two categories I’ll be using to evaluate the quarterbacks are “adjusted completion percentage”* and “adjusted yards-per-aimed-throw”**

*(Completions + Drops) / (Pass Attempts – Batted Balls – Throwaways – Throws Disrupted by a Hit – Spikes)
**Passing Yards / (Pass Attempts – Drops – Batted Balls – Throwaways – Throws Disrupted by a Hit – Spikes)

What we see here is quarterbacks progressively completing fewer passes (for the most part) as defensive backs are added to the field. The gradual drops aren’t severe, but they are noticeable. The aYPA category is quite a bit more volatile. Ignoring the relatively small sample sizes when three or seven defensive backs on the field, we’re left with Base, Nickel, and Dime. Against Base, we see a strong 8.6 aYPA. That figure dips to 7.8 when Nickel is on the field, but hops back up to 8.0 against Dime.

That probably seems odd, but it does add up. Defenses don’t use the Dime very often (16 percent of passes during the 2012 season), and are generally only in it when it’s an obvious pass situation. These come in what you’d usually define as “Garbage Time,” which means the offense is taking shots down field in hopes of quickly finding big yardage. That being the case, it makes sense that we’d see lower completion percentages and higher yardage marks.

The next step of my study was to compare the actual and expected aC% and aYPA of each qualified quarterback. The expected marks were simply a calculation of what the league average quarterback would’ve achieved against the actual defensive packages faced by the quarterback in question.

Our first chart shows the quarterbacks who had aC% marks well above what was expected based on the packages they faced. You’ll notice that most quarterbacks have expected marks right around the 72 percent league average. This is because most throws come against either base or nickel defenses. As we learned in our earlier chart, the league-average difference in completion percentage between the two packages is only 2 percent. So, although this will look similar to a chart showing the league leaders in completion percentage, I included it anyways since it is tweaked to show the impact defensive personnel packages had on the numbers. For the same reason, I won’t go into too much analysis. You get the point. Here are the quarterbacks with the worst dropoff from what was expected:

Next up, we’ll compare actual and expected aYPA marks. The expected marks are still a bit closer together, but there’s enough separation to make these more interesting than aC%. Over 500 aimed passes, for example, the difference between Peyton Manning’s league-low and Colin Kaepernick’s league-high expected YPA marks is just under 212 yards.

Here are our leaders…

…and here are our duds:

I think these final four charts make it pretty clear that the difference between facing base or nickel is not too impactful on a quarterback’s production. There’s clearly a slight advantage to throwing with one less defensive back on the field, but it’s not as much as you might expect.

Another way to look at this would be to weight the “expected” statistics based on both the number of defensive backs and the number of wide receivers. I did run that study and found that the four charts looked almost exactly the same. There was a bit of movement, but considering that most defenses will send in a third corner when an offense adds a third wide receiver, it makes sense that the change would only be slight. For that reason, I won’t waste space adding four more charts to the article.

Research on the impact of defensive personnel packages on quarterbacks and running backs has been telling, but there’s still a long way to go in the quest to normalize each throw and rush attempt. As always, I’ll be continuing that research throughout the spring and summer months. Stay tuned.

Follow Mike Clay on Twitter: @MikeClayNFL