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The NFL's Luckiest Team

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The Jets greatly overachieved in 2013 based on their point differential. Will 2014 see them regress towards the mean?

Rich Barnes-USA TODAY Sports has an interesting statistic called the Expected W-L for each team, which purports to calculate what record each team "should" have had based on their respective point differentials. In 2013 only six teams in the NFL had a worse point differential than the Jets' -97. None of those teams won more than four games. So it should come as no surprise that according to PFR the Jets "should" have won only 5.4 games in 2013. The 2.6 games difference between what the Jets "should" have done and the record they actually wound up with was the largest such difference in the NFL, by a fairly wide margin. The Colts were a distant second with a 1.6 win difference between their expected win total of 9.4 and their actual total of 11. Based on this PFR statistic, the Jets were, in a sense, by far the luckiest team in the NFL in 2013. In fact, it goes beyond 2013. The 2013 Jets were actually the team with the worst point differential in NFL history to finish .500 or better.

Now, understand that by "luckiest", we are not referring to any specific plays such as, to give just one example, the end of the Tampa Bay game, which some said the Jets were very lucky to win. This is a very specific meaning of the term "lucky", wholly unrelated to any specific game circumstances or outcome. When we say "lucky" here, we are simply referring to the difference between what a team with the Jets' point differential would historically have been expected to achieve in terms of total wins and what the Jets actually achieved, regardless of any individual plays, games, referee's calls, or other circumstances. Any who object to the use of the term "lucky" in this specific sense may have a point, but I use the term simply as shorthand for the much more unwieldy "the difference between expected wins and actual wins based on the difference between any given team's points scored and said team's points allowed over the course of an entire season." Perhaps you'll agree the term "lucky", for all its limitations here, is better than that mess of a mouthful of words.

For those with an unnatural and possibly unholy addiction to the mathematical details involved in esoteric statistics like Expected W-L, I give you this quote from PFR explaining the derivation of the stat along with the actual formula used to calculate it:

In the early 80s, or possibly even before that, Bill James noted that baseball teams' true strengths could generally be measured more accurately by looking at runs scored and runs allowed than by looking at wins and losses. To be more precise, he found that one can predict future win/loss records more accurately using only past runs scored and runs allowed than using only past wins and losses. To put it another way, if a team had a record of 82-80, but their runs scored and allowed totals were more in line with those of a 76-86 team, then that team should be treated as a 76-86 team for the purposes of predicting next year's record.

So what record "should" a team with RS runs scored and RA runs allowed have had? James came up with the formula:

Expected record =~  -----------
                    RS^2 + RA^2

Because it has some superficial similarities to the Pythagorean Theorem about right triangles that you learned at some point in your youth, it came to be known by the same name. As it turns out, though, you can replace the 2s in the exponents with 1.82s and get slightly better predictions. For football, people have found that an exponent of 2.37 seems to work best. So the Pythagorean Theorem for football looks like this:

Expected record =~  -----------------
                    PF^2.37 + PA^2.37

Needless to say, that's a bit of a mouthful. What may be important to note from the Jets' standpoint is that it is well documented that teams that perform substantially better (or worse) than the formula says they "should" in any given year have a pronounced tendency to regress toward their Expected W-L the following year. In other words, all other factors being equal, if the Jets went into next season with the exact same team, physically frozen in age (an impossibility, but humor me here), and played the exact same schedule, it is far more likely they would wind up with 5 or 6 wins than it is they would end up with 8 wins. Of course, next year the team will be substantially different, with numerous free agent and draft pick additions, as will every other team in the league. But what the Expected W-L purports to tell us is that we should probably consider the baseline team the Jets will be building from in the offseason to be a 5.4 win team, not an 8 win team. If that is correct, then it follows that the Jets are much farther from being a playoff team next year than most people would probably guess based solely on their actual record in 2013. In fact, if the Expected W-L figure is reasonably accurate, the Jets may have to add enough assets to make a whopping 5 win difference over the offseason in order to comfortably expect a playoff berth in 2014. That is a huge amount of wins to add in one offseason, and if that is even close to accurate, John Idzik and the Jets have their work cut out for them. They will have to make every free agent acquisition and every draft pick count if the Jets are to be serious contenders in 2014.

Of course, such statistics are far from infallible, and history is not destiny. As proof one need look no farther than the 2013 second luckiest team, the Indianapolis Colts, with 1.6 more wins than their Expected W-L would indicate. Which team was the 2012 "luckiest" team? The very same Colts, with a whopping 3.8 more wins than Expected W-L would indicate. So the Colts at least bucked the odds two years in a row. On the other hand, they also experienced a pronounced regression toward the Expected W-L number, as they shaved 2.2 wins off their "luck" in 2013.

Will the Jets experience a similar regression in 2014? There's no way to know. But if history is any guide, it is a pretty good bet they will. And if they do, the only thing that will save a space in the 2014-15 playoffs for them, and the only thing that will likely save Rex Ryan's job, is a spectacularly successful offseason of big upgrades in personnel. Without a great offseason, the Jets may be headed for yet another year of mediocrity. And Rex may have one foot out the door. John Idzik, your move.