Why Improved Passer Rating Differential Will Carry Cowboys To 2016 Playoffs

One of the most misused and misinterpreted stats from last year are the passing yards the Cowboys allowed. Over 16 games, the Cowboys allowed 3,636 passing yards, the fifth lowest value in the league. Does that mean the 2015 Cowboys pass defense was a top five unit? Not by a long shot.

For decades, the NFL and the people who are paid to report about the NFL have conditioned us fans to look at volume stats like the ones above, yet the number of yards you accumulate or give up has almost no correlation with whether you win or lose a game in the NFL. How much someone passes or runs for can make for nice anecdotal discussions in the context of fantasy football, but has next to nothing to do with winning in the NFL.

Today, winning in the NFL is all about passing efficiency. The best offenses are those that pass the ball the most effectively, the best defenses are those that prevent their opponents from passing effectively. The best teams in the league are those that do both.

The key to the Cowboys making the playoffs will be an improved passer rating differential. Don't trust anybody who tells you otherwise.

Over the last seven seasons, the Cowboys offense has ranked in the top ten as measured by offensive passer rating (OPR) in five seasons. Only in 2010 and 2015, when Tony Romo missed significant playing time due to injury, did the Cowboys passing offense fall out of the top 10. Here's what the last seven years look like from a passer rating perspective.

At first glance, this may not appear like a particularly impressive table, especially with last year's dreadful performance still fresh in our minds - minds firmly in the grip of recency bias.

But consider that over the last seven seasons, only three teams have had a top ten passing offense more often than the Cowboys did. The Saints are the only team to finish in the top ten in OPR in every one of the last seven seasons, the Patriots and Packers managed that feat six times, and the Steelers are tied with the Cowboys at five seasons. That's pretty good company to be in.

In terms of offensive passer rating, the Cowboys (92.7 rating) rank fifth overall over the last seven years behind the Packers (101.6), Saints (99.4), Patriots (97.8), and Chargers (94.7).

It took the football public a while to wake up to this, but the Cowboys have one of the top passing attacks in the league, led by one of the top QBs in the league. And with Romo back healthy, there's every reason to expect the Cowboys to finish as one of the top passing attacks again in 2016.

Unfortunately, the same cannot be said of the Cowboys' pass defense. Here's how the Cowboys have ranked in defensive passer rating (DPR) over that same period.

The Cowboys pass defense finished outside the top ten in every one of the last seven seasons. Their defensive passer rating over the last seven years of 89.4 ranks 27th in the NFL over the period, ahead only of such illustrious pass defenses as the Raiders (89.9), Bucs (90.6), Redskins (91.0), Vikings (92.4), or Jaguars (93.0).

Over the last seven years, the Cowboys have combined a top ten passing attack with a bottom ten pass defense as measured by passer rating. Some might take this as a sure sign of the ineptitude of the Cowboys' talent acquisition process, others will recognize that this is simply what a team looks like that defines itself by its offense, not by its defense, as David Moore of the Dallas Morning News recently pointed out when the Cowboys picked RB Ezekiel Elliott over Jalen Ramsey:

The Cowboys don't ignore defense. They simply don't place a premium on acquiring blue chip talent on that side of the ball the way they do offensively.

This isn't an indictment. Every team in the league operates with an offensive or defensive bent. The goal is to excel on one side, establish an identity and make sure the other side doesn't drag you down. It can become a partner in victory, but is rarely an equal partner.

In the Cowboys world view, Elliott is more significant than Ramsey. It's about offense first. It's part of their DNA.

We know that passer rating and more specifically, passer rating differential (PRD), is one of the stats most closely linked to winning in the NFL. And one of the interesting things about PRD is that it can be plugged into a very simple formula to predict win totals in the NFL. The PRD formula (Projected Wins = PRD*0.16+8) has shown a fairly close correlation with the Cowboys' actual wins over the last few years, as the table below illustrates

The mean absolute error (the average of the absolute deviation between the projected and the actual win total) is quite low at 0.9 for the Cowboys over the last seven years using our little formula, a strong indication that the formula is a good projection tool.

So what does all this mean for the 2016 Cowboys? The Cowboys' best chance for improving their W/L record in 2016 is to improve their passer rating differential. And going by the PRD formula, these are the differentials they'll need if they want a winning record in 2016:

9 wins: 6.3
10 wins: 12.5
11 wins: 18.8
12 wins: 25.0

At the end of the day, if the Cowboys want to succeed in 2016, they'll have to fix their passer rating differential. How they go about that, via an improved pass rush, improved secondary or an improved offense, is largely a philosophical question.

You tend to win games when you pass the ball effectively - or prevent the other team from passing effectively. The teams that do both usually end up in the playoffs. And if the Cowboys passing offense finds its way back to being a Top 5 unit, the Cowboys will make the playoffs, even if their pass defense remains in the bottom half of the league.