At the end of each season when I was coaching -- and every year since -- I have tried to do a detailed analysis of the four teams that made it to the conference championship games. My goal is to see what major factors contributed to their success, what commonalities existed among them, and to find out a little more about the direction in which the game is headed.
This year's teams present an interesting mix of proven axioms about winning and unique outliers that could give the numbers-crunching analytics guys a headache.
Here are my four biggest takeaways from the teams playing for their respective conference titles:
Tried and true
"Play good defense and run the ball" is a familiar refrain that defines both NFC representatives, Arizona and Carolina. Both finished the regular season ranked in the top 10 in rushing and total defense.
Carolina's formula is to take the sixth-ranked defense in the NFL (plus a league-leading turnover differential) and combine it with the most physically punishing rushing offense in football. What's generally in vogue now in the NFL is to have diversity in the backfield, with both a fleet-footed runner who can get to the edge and be a factor in the passing game, as well as a bulldozer who can gain tough yards up the middle. That's not the Panthers. They pound away with Jonathan Stewart, then pound away some more with Mike Tolbert. Oh, and then they beat you into submission with their 245-pound quarterback, Cam Newton.
Arizona can match the Panthers' defense stat for stat, with one of the best cover groups in the NFL, even after the loss of safety Tyrann Mathieu. Add to that the eighth-best rushing attack in the league. Most people are surprised to see that the Cards are ranked that high in running the football -- especially considering they finished 31st in 2014. Well, free-agent addition Chris Johnson gained 814 yards in the regular season, while rookie David Johnson added 581. Together, they helped to transform Arizona from a team that ran only because it had to try it once in a while -- to keep the defense honest -- to a team that uses the running game consistently.
Stop making sense
Denver and New England are clear outliers when it comes to the simple formula of playing good defense and running the ball, as neither team's ground attack ranks in the top half of the league.
That was the formula Gary Kubiak and John Elway sold to Peyton Manning as the key to getting back to the Super Bowl this season. They delivered with Wade Phillips' defense: The Broncos rank No. 1 in the NFL in total defense and among the top 10 in third-down efficiency, and they gave up fewer big plays than any other D. But the other half of the equation, the running game, hasn't quite worked out as planned. Denver shows flashes on the ground, but consistency is a major issue. The Broncos ranked 17th in rushing yards during the regular season.
New England also boasts a top-10 defense, but the Patriots' run game is even more underwhelming, ranking 30th. The difference is, the Pats don't seem to care much about the ground ineptitude. They are only ranked that low in rushing because of the truly unique way they approach game planning. In their divisional playoff win over the Chiefs, the Patriots attempted just 14 rushes -- not because they could not run so much as that they simply chose not to. In fact, New England's first 14 offensive snaps of the game were pass plays.
The ability to carry your team when you have to attempt 40-plus passes is a telling number for quarterbacks. Tom Brady is 46-26 when attempting 40-plus passes in his career, an astounding 64 percent winning rate. By comparison, Manning is just 46-49, Carson Palmer is 11-30 and Newton, in his young career, is 2-4-1.
It takes all kinds
All seven of the newly named head coaches during this hiring season specialize in the offensive side of the ball. This is cyclical, as last year's hires showed an emphasis on defense, with Dan Quinn, Todd Bowles, Rex Ryan, John Fox, Jack Del Rio and Jim Tomsula all landing jobs.
On Championship Sunday, we'll see a balance, with two offensive guys (Bruce Arians and Kubiak) and two defensive guys (Bill Belichick and Ron Rivera). The same was true for the Divisional Round, where the makeup was evenly split, four and four.
Same as it ever was
In a league dominated by quarterbacks, the final four features four accomplished players at the crucial position. Three of the four starting quarterbacks went No. 1 overall in the NFL draft. Brady, of course, is the ultimate draft-day steal, taken in the sixth round, No. 199 overall. Also of note is that two of the top overall picks (Manning and Palmer) are no longer with their original teams. Six of the eight teams' quarterbacks in the Divisional Round were taken in the first round, with Russell Wilson being the only other later-round choice besides Brady.
Finally, the elite teams are no strangers to this stage. Yes, there were a lot of new faces among the playoff teams in the NFL this season -- party-crashers from Washington to Kansas City, Houston to Minnesota. But of the last four teams standing, all four are repeat playoff qualifiers. This is Arizona's second straight playoff trip (it could be three straight, as they went 10-6 in 2013), Carolina's third straight, Denver's fifth straight and New England's seventh straight. One thing that's usually true: When it comes to the final four, you find a lot of the usual suspects.
Follow Brian Billick on Twitter @coachbillick.