Regardless of what happens on the football field, whether it be a touchdown, an interception, a 100-yard rushing performance or a blowout victory, we seek an explanation. Why did Tony Romo throw three interceptions against the Redskins in Week 17? It's natural to search for answers.
Sometimes, though, there's no real good answer for why things happened the way they did, even in football. Call it randomness, luck or whatever you'd like, but there's a lot more of it inherent to the game than most of us know or would like to admit. A big reason for that is it can look cowardly or unintelligent to admit that we don't know something. Writers and analysts are expected to have all the answers, so it's not a particularly good look to answer the Romo question with, "I don't know, it just happened. He got unlucky."
That's not meant to be a cop out for Romo or a declaration that everything is random; lots of things that happen in the NFL can be logically explained. Why did the Patriots go 12-4 and the Cardinals 5-11 last year? Well, one is a good team and one isn't; there's not too much luck involved there. But lots of other phenomena – the bounce of a fumble, a sudden gust of wind on a crucial overtime pass, an illness striking the majority of players on a team – are the product of randomness, yet we characterize a team's fate as if there was no luck involved at all.
Bill Parcells used to say that "you are what your record says you are." I respectively disagree. I have a feeling that fans of the Cardinals would do the same; their team started the 2012 season with four consecutive wins, including victories over the Patriots and Seahawks. Were the Cardinals 4-0? Yes. Were they a 4-0 caliber team? Not at all, and we'd be doing a disservice to intelligent football analysis to stubbornly argue that they were just because that's what the record indicated.
The great thing about luck is that it evens out over the long-run. Over the short-term, meaning a season or even two, however, it can really affect team performances. One of the primary things I try to accomplish in my articles is to sort luck out of the equation as much as possible. If we can do that, we can inspect the true "essence" of each team, allowing us to make accurate predictions because we know long-term luck just doesn't exist.
Points Scored, Expectations and Randomness
When you hear Joe Buck cite the offensive ranks for each team playing on FOX on Sunday afternoon, you're typically hearing where they stand in terms of either total points or total yards. I've explained in the past that those are really poor measures of offensive talent because they do little to isolate an offense from their defense and they don't account for things like tempo or game situations.
I've also explained why a better metric, perhaps the best out there, is Expected Points Added. EPA is a measure of how many points an offense "should have" scored based on how they played. It factors in historic success rates and game situations to determine the most likely outcome in any particular situation. A first-and-10 at your own 20-yard line has historically been worth a net of 0.34 points, for example. Because of that, an offense holding possession in such a situation at the start of the third quarter would be a slight favorite to win the game – at about 52 percent – given that the score is tied and their EPA is positive.
In any event, EPA is awesome in that it does a really solid job of capturing performance independent of luck; it's primarily a measure of how many points a team should score given how they perform in specific game situations. Like head coach Jason Garrett, EPA intelligently emphasizes the process over the results.
So we have a metric that is filled with noise (total points) and one that's not (EPA). If we compare the two, we should get a decent idea of which teams got the luckiest. That is, which overachieved and which underperformed relative to how well they actually played.
Points Scored versus EPA
Below, I charted each team's rank in total points and EPA, along with the difference between the two.
The teams listed at the top are those that ranked much higher in EPA than in total points. In essence, we're saying that those squads should have scored more points given the quality with which they moved the football on offense.
The Panthers are a really interesting case because they were very efficient in Cam Newton's second year, ranking in the top 10 in EPA, yet they finished just 18th in total points. The conclusion we can draw is that if the Panthers' offense performs exactly the same in 2013 as last year, they're far more likely to finish ninth in points than 18th. And just like that, we've uncovered a "sleeper" team likely to improve upon their 7-9 record, even in the competitive NFC South. [embedded_ad]
At the bottom of the list, we see the Bengals and Bears – two teams that wildly outperformed expectations in 2012 by posting a combined 20-12 record. Even if their offenses remain the same in 2013, they're likely to both end up in the bottom half of the league in points scored.
The NFC East
The Cowboys, who ranked 15th in the NFL in points last year, checked in at 14th in EPA. That means that, based on how they performed offensively, the 'Boys pretty much scored as they should have. It's good that the team wasn't unusually lucky in 2012, but it also means they'll need to improve their efficiency to become a top-10 offense. We know they have that potential.
The Eagles, who ranked 29th in points, underachieved just a bit. Based on how they played, they'd typically rank three spots higher. Both the Redskins and Giants experienced a good deal of luck, however. They ranked three and four spots higher than they should have, respectively, suggesting that even comparable 2013 play will result in a decline in points.