Predicting NFC Playoff Success

There are two weeks left in the NFL regular season, and while the Vikings have not quite clinched a playoff spot, current estimates give the Vikings a 95% chance of doing so. The only way for the Vikings to not make the playoffs at this point is if they lose their last two games and the Rams win both of theirs.

And, apart from the winner of the NFC East, all the other NFC playoff teams have already clinched a playoff spot.

So, barring the Vikings losing both their games and the Rams winning both of theirs, the NFC playoff teams will be: San Francisco 49ers, Seattle Seahawks, New Orleans Saints, Green Bay Packers, Vikings, and either the Cowboys or Eagles.

I’m also gonna go out on a limb and say the Cowboys will win the NFC East by beating the Eagles next weekend in Philadelphia. They beat them 37-10 earlier in the season, and for my purposes here, it’s pretty clear the Eagles would be the weakest team in the NFC playoffs if they made it, so it’s not really worth adding them to the analysis at this point.

What Are the Key Predictors of Playoff Success?

In the recent past, there are a few indicators that have a pretty high correlation to playoff success in the NFC.

Playoff Seed

The first indicator is an obvious one: playoff seed. The top two seeds have a first-round bye, and host the division round matchup. In the last seven years, one of the top two seeds have won the NFC Championship every single year. And in 5 of the last 7 years, the top two seeds have faced off in the NFC Championship game.

The reason is simple: win one home game after a week off and you’re in the NFC Championship.

The other thing about the top two playoff seeds: they’re usually pretty strong in other predictive metrics for playoff success. But not always.

And when that’s not the case, that’s when you see some upsets.

Point Differential

Another predictive metric for playoff success is point differential, or the total points scored minus total points allowed during the regular season. Often, the top seeds also have the best point differential. But not always.

In 6 of the last 9 seasons, the team with the best point differential won the NFC Championship. Last year the Saints had the best point differential, but lost in the Championship game to the Rams, who had the 2nd best.

In 2012, the 49ers had the 2nd best point differential and won the Championship by beating the Falcons, who had the 3rd best. The Seahawks had the best point differential that year, but lost the NFC West to the 49ers and the divisional round to the top seeded Falcons.

And in 2013 the 49ers were the 5th seed, but had the 2nd best point differential after the Seahawks. They went to the NFC Championship but ultimately lost to the Seahawks.

The Packers also led the NFC in point differential back in 2010, but lost the NFC North to the Bears and became the 6th seed. They went on to win the NFC and Super Bowl.

So, if a playoff team has a low seed, maybe a wild card team, but also a top point differential, that is a pretty good indicator of a team that could still make a deep playoff run.

Another interesting aspect of point differential is not just the ranking, but the raw number as well. Only one team with a point differential of less than 100 has won the NFC Championship in the past decade - the anomaly that was the 2011 Giants. And only one other time, the 2016 Packers, did they make it to the NFC Championship game - and they got blown out 44-21 by the Falcons.

PFF Overall Grade

This is the overall cumulative grade of a whole team by PFF using their grading methods. It generally corresponds to the overall quality of a team’s roster and how well they’ve played.

Often times the overall grade PFF gives a team tends to correspond to their playoff seeding, although often those grades can be pretty close. In any case, a low seeded team that has a relatively high PFF overall grade can sometimes pull off some upsets.

For example, in 2013 the Saints were the 6th seed, but 2nd in overall PFF grade, and went on to beat the 3rd seeded Eagles before succumbing to the top graded, and seeded, Seahawks.

In 2017 the Falcons were the 6th seed, but had the best overall PFF grade for the regular season. They beat the 3rd seeded Rams, and nearly beat the top seeded Eagles in the divisional round - losing on a final goal line stand by the Eagles as time expired.

ANY/A

This is an acronym for Adjusted Net Yards per passing Attempt, which is a key metric for quarterback efficiency and overall success of a team’s passing game.

The formula for calculating it is as follows: (Passing Yards + PassTDs * 20 – INTs * 45 – Sack Yards Lost) / (Pass Attempts + Sacks).

In a passing league, having a good passing attack is essential. It is also sometimes seen as a predictor of success, including playoff success, as good teams typically have a QB with a relatively high ANY/A. But looking back over the past 7 years of the NFC playoff tournament, this hasn’t been so much a predictor of success as a precursor.

What I mean by that is that lower seeded teams with a higher ANY/A, - like the 2015 Seahawks or 2013 Saints or 2010 Packers - also had higher PFF grades and/or point differentials, which have more predictive value.

Key Injuries

One final factor that can influence playoff success are key injuries. And that can work both ways. Sometimes a team suffers a key injury or two that can derail their playoff success, despite looking good in the other metrics. On the other hand, sometimes a team that has suffered key injuries during the season, but either gets those injured player(s) back or is able to overcome their loss (by having a guy who perhaps started slow but develops well), can do better than their regular season predictive stats would indicate.

Such was the case with the 2017 Eagles, who lost Carson Wentz late in the season and turned to Nick Foles. Foles struggled mightily the first few games, but improved during the playoffs. The same was true for the Eagles in 2018, when Wentz was out late in the season, and few other key players had been hurt and/or missed time during the season, but were able to play against the Bears in the playoffs and won a close game on a missed Bears field goal to end the game. But Wentz was out the next game against New Orleans and they lost.

Other Predictive Stats

I looked at other predictive stats - like Football Outsiders’ Weighted DVOA - which is meant to show which teams have been playing the best at the end of the regular season, but didn’t find that it added much to what the other predictive stats where revealing, and sometimes it clouded the picture. For example, in 2017, the Saints and Rams had the two highest Weighted DVOA percentages at the end of the regular season, and Atlanta was last.

But There Are Exceptions Too

Of course there are examples where no predictive stats could explain the outcome. The 2011 Giants are probably the best example of that. A 4th seed with the worst record and point differential, there was nothing to explain their upset blowout of the top seeded Packers, nor their overtime win over the 49ers. But they beat them both and won the Super Bowl too.

The 2016 Packers beating the top seeded Cowboys wasn’t predicted by any of these metrics either, although it was a very close game won on a last second field goal. There wasn’t much to suggest the Cowboys would beat the Seahawks last year either, although the Cowboys did get some key players back from injury for that game.

But even the more predictable outcomes are often close games decided by a key play or two.

But if you look down the list of playoff teams, matchups, and outcomes, you can see why the Rams and Saints made it to the NFC Championship last year, or why the 6th seeded Packers in 2010 won it all. You could also predict that the 6th seeded Seahawks would beat the 3rd seeded Vikings in 2015 - but not necessarily the weather or how it happened.

Take a look at this decade’s NFC playoff predictive stats along with the results each year:

So What Does That All Mean For This Year’s NFC Playoffs?

While all the seedings have yet to be decided, and some of the predictive stats could change over the next two weeks, this year’s NFC playoff tournament is shaping up to be an unusual one compared to the last couple seasons.

First off, there’s no clear top seeds as there have been most years in the past decade, including the last couple, based on the predictive stats. In fact, you could make a pretty good argument that the current last three seeds look more compelling than the first three - based on the predictive stats.

It wouldn’t be surprising if the Packers fell to the #3 seed, if they lost to the Vikings Monday night as the predictive stats would seem to indicate, and the Saints won the rest of their games. The other more possible change in the seedings would be if the 49ers were able to beat the Seahawks week 17, which would give the 49ers the top seed or at least a first-round bye, and the Seahawks the #5 seed. That would be somewhat more in-line with the predictive stats, but there are also injuries to consider.

The 49ers lost three key players prior to their loss against Atlanta - Richard Sherman their best starting CB, their starting center Weston Richburg, and edge rusher Dee Ford, who was 4th in QB pressures on the team, despite missing time earlier in the season as well. Richburg and Ford are lost for the postseason as well, while Sherman is hoping to come back from his hamstring injury in time for the playoffs.

The Seahawks and Saints also have some injury issues of late. The Seahawks lost their 2nd RB in Rashaad Penny, and key DE Jadeveon Clowney is battling a sports hernia type injury that will likely limit him for the rest of the regular and post season. They also lost WR Josh Gordon to suspension, although he didn’t have a big impact statistically in their offense. The Seahawks also have some offensive linemen who’ve been battling injuries - being limited in practice every week as they head into the home stretch.

The Saints lost two impactful defensive linemen in Sheldon Rankins and Marcus Davenport. Davenport was 2nd in QB pressures on the season, while Rankins was a stout interior defender. Starting right guard Larry Warford was also carted off Monday night with a knee injury.

All this further clouds the NFC playoff picture going into week 16.

And For the Vikings ?

If the Vikings beat the Packers on Monday night, the most likely outcome is that they’ll play the Packers again in Green Bay in the wild card round. The Predictive stats would seem to give the Vikings a pretty good shot at upsetting the #3 seed at home, however.

In fact, given the Vikings’ ranking in the predictive stats currently, they look as good as any team in the NFC to win it all - albeit on a much tougher road as a likely wild card.

A win in Green Bay, should it play out that way, would most likely result in the Vikings taking another trip to the west coast and either a re-match against the Seahawks or matching up against the 49ers in Santa Clara, depending on which team wins their week 17 tilt.

If the Vikings made it that far, I suspect they’d most likely meet the Saints in the NFC Championship in New Orleans, with all the fond memories from 10 years ago. The predictive stats are pretty even on that match-up right now.

Stay tuned.