As a younger dude, I can't pretend to know everything about rock 'n' roll. However, I know that Aerosmith is a good American rock band.

We can use some of their lyrics to perfectly describe this year's Atlanta Falcons: It's the same old story, same old song and dance, my friend. It's the same old story, same old story. Same old song and dance.

While the Falcons brought in a completely new coaching staff this offseason, the result appears the same as always -- the Falcons falling short of expectations. At 6-5 through Week 12, memories of a 5-0 start seem like they're from years ago, not weeks ago.

What happened? How did things go south so fast? Let's take a look at some math and figure out where it all went wrong.

Consistent Mediocrity

While the Falcons got off to one of this season's best starts at 5-0, the undefeated start was quite deceiving.

Through Week 5, the Falcons ranked sixth in nERD, or the number of points our algorithm would expect an team to win by against an average squad on a neutral field. And, really, our Net Expected Points (NEP) show that pieces of the team were performing at a pretty high level.

Of 35 quarterbacks with at least 75 drop backs at the time, Matt Ryan ranked fifth in Passing NEP (53.42) and eighth on a per drop back basis. Meanwhile, Julio Jones was the second best receiver in football according to Reception NEP.

Devonta Freeman led 49 running backs with at least 31 carries in Rushing NEP (19.39), was third in Rushing NEP per play (0.21), and was sixth in Success Rate (49.46%). As a receiver, he led 48 backs with 10 or more targets in Reception NEP (17.75), was 10th in Reception NEP per target (0.57), and was 5th in Reception Success Rate (77.42%).

With an offense rolling behind two of the leagues best players at their positions, Freeman and Jones, and Ryan playing really well at quarterback, a drop off looked near impossible.

But the team's best win over the first five weeks of the season came against Houston, a team currently ranked 13th in nERD. But we all know Houston's improved dramatically since, and they actually were listed as the 23rd best team when the Falcons faced them.

In other words, Atlanta wasn't really tested.

The Falcons' first real opportunity to show legitimate improvement came in Week 6 against their rivals, the 30th ranked Saints, while on primetime national television. Instead, they lost 31-21 and started their 1-5 skid. Over the past seven weeks, the Falcons have not faced any opponents in our top 10 nERD, with only a sloppy victory over the 22nd-ranked Titans, and another loss against the 31st ranked 49ers. 

So much for early season improvement.

What Happened?

When the Falcons hired Dan Quinn this offseason, he was brought in to make the Falcons defense perform at the level of his former defense, the Seahawks. Last year, the Seahawks finished the year ranked third based on Adjusted Defensive NEP while the Falcons were ranked 29th. 

Through Week 5, the Falcons ranked 16th in Adjusted Defensive NEP, 20th against the pass and 16th against the run. The Falcons had played zero teams who ranked in the top-10 offensively in terms of Passing NEP, and only one that ranked in the top-10 for Rushing NEP. As a defense, they were challenged minimally, but they did not look great.

While the Seahawks remain in the top-seven across the board based on our defensive metrics, the Falcons are now 22nd overall.

The run defense has risen to the challenge since Week 5, as they've faced four teams who rank in the top-12 within our Rushing NEP metric, strengthening their ranking from 16th to 10th in against the run. And the pass defense has actually remained in a similar spot since Week 5, going from 20th to 21st.

In other words, the Falcons defense is playing around the same level it did during the 5-0 stretch to start the season. 

The offense isn't.

As noted above, Matt Ryan started the season off in efficient fashion, with a Passing NEP per drop back of 0.27. That's fallen to 0.20, which is still good, but also significant considering the level he was playing at. For context, that's the difference between Jay Cutler, who's having a fantastically underrated season, and Josh McCown.

That hasn't impacted Julio Jones' cumulative numbers, as he's still third at wide receiver with a 96.49 Reception NEP on the year. But on a per target basis, Jones has gone from ranking 24th at the wide receiver position to 55th. Though Jones is posting huge numbers, he's pacing towards his worst season from an efficiency standpoint.

Losing Devonta Freeman for a couple of games hasn't helped things, either. Tevin Coleman inadequately replaced him, as he ranks 48th among the 54 NFL backs with 50 or more touches in per rush efficiency.

Really, what happened to the Falcons is they started regressing. Ryan isn't sustaining his incredible efficiency, which is impacting the rest of the offense. And that's hurt them in the win column.

Weak Finish

Even with the return of Freeman, the Falcons are not projected to make the playoffs. They're currently the 15th ranked team in our Josh Norman and the Carolina Panthers looming, too. The Falcons won't be projected to win either of those matchups, and they have a tough game in Tampa Bay this weekend. While contests in Jacksonville and at home against New Orleans appear softer, both teams can attack the Falcons weakness: their pass defense.

Missing the playoffs this year should come as no surprise, but with the way the Falcons have cooled, it may even be challenging for them to finish .500. More change needs to come if the Falcons want to improve on the field.