"You are what your record says you are."
Bill Parcells' famous quote about the NFL brilliantly expressed the importance of not making excuses and playing the "what if" game in an NFL locker room. Teams win and lose games, and all the justification in the world doesn't change that.
Unfortunately, Parcells' truism is also completely useless for understanding what is going to happen in the future.
This week's advanced stat is Pythagorean wins.
The concept is simple, even though the math is tricky. The idea is that over time, a team's point differential (points scored minus points allowed) is a better indicator of how that team will perform in the future than their record is.
For example, a team that is 6-2 but has been outscored by five points on the season because of a couple of blowout losses is more likely to play like a 4-4 team going forward than like a 6-2 team.
While fans like to point to a team's record and crow, often times there are warning signs that the luck is about to run out. The same can be true for a struggling team that has actually outscored opponents on the season. This relationship between future wins and point differential is not debatable.
For the purposes of projection into the future, you are better off looking at Pythagorean wins than real wins. The 2010 Packers won 10 games on the field, but were dominant on the field, leading the NFC in point differential. They weren't really a 10-win team sneaking into the playoffs on tiebreakers—they were really a juggernaut with some bad luck. The playoffs revealed the truth.
There are many different ways to calculate this number, but they all are based on essentially the same components: "points for" and "points against." This can be a handy tool for predicting a big fall from a team with a good record, or a big leap forward from a team that had some bad luck. No statistical tool is right all the time, but Pythagorean wins has a good track record and is far more useful than actual wins for predicting the future of a team.
Pythagorean wins nicely reflect the realities of the 2011 Tennessee Titans. The Titans had a disappointing season in 2010, winning only six games. The losses and subsequent organizational stress helped lead to the departure of long-tenured head coach Jeff Fisher.
Still, there were positive signs for the Titans. They endured two painful quarterback changes as both Kerry Collins and Vince Young suffered injuries. Despite the upheaval, the Titans still managed to outscore their opponents for the year by 17 points. Essentially, they were a .500 team that had a little bit of bad luck.
That luck evened out in 2011. With more stability at quarterback thanks to the signing of Matt Hasselbeck and some timely play by Jake Locker, the Titans won nine games, falling just shy of making the playoffs. In the standings, the team improved by three wins and left the fans feeling upbeat.
The numbers say that was a bit of a mirage. The Titans only outscored opponents by eight points on the year. This means that they were an 8-8 team that happened to win an extra game. Given that they barely pulled off a win at Houston against the Texans' subs the last week of the season, that estimate feels accurate.
The standings say the Titans were significantly better in 2011 than in 2010. The numbers say they were almost the same team, with a little more luck and stability.
For the Titans to cross the 10-win threshold and make the playoffs in 2012, they'll need real improvement in key areas. They can't count on their luck evening out.
It already did.