Which teams were luckiest in 2006?

When we are engaged in any endeavor, we know we shouldn't think about how much luck has to play in the outcome. It is usually counterproductive to dwell on luck because that tends to reduce our efforts towards our goal. Think about it--Why should I try so hard if it comes down to luck anyway?

In the NFL, if teams thought that way they'd probably be dead meat. But luck is a factor in all sports. Think about a very simple example game. Assume both PIT and CLE each get 12 1st downs in a game against each other. PIT's 1st downs come as 6 separate bunches of 2 consecutive 1st downs followed by a punt. CLE's 1st downs come as 2 bunches of 6 1st downs resulting in 2 TDs. CLE's remaining drives are all 3-and-outs followed by a solid punt. Each team performed equally well, but the random "bunching" of successful events gave CLE a 14-0 shutout.

The linear efficiency model I've began using early in the season has an r-squared value of almost 0.75. That means that 75% of the variance in the outcome (season wins) can be explained by the model's variables. But by including additional variables such as penalty yards or special teams the r-squared only marginally increases and they are largely insignificant. Those factors are fairly random and chaotic anyway, which is one way to define luck. So we could conjecture that a measurable part of a team's win-loss record, but something less than 20% is due to luck.

So how can we determine how lucky a team is? By using the model and estimating the number of wins a team "should" have based on its stats, the number of "expected wins" is calculated. The difference between a team's actual wins and its expected wins reveals how lucky a team is.

Seattle appears to have been the luckiest team this year, winning about 4 more games than we would expect given their stats. They squeaked out 1 game over .500 in a very weak NFC-West to make the playoffs. If they were in the AFC they probably would not have made the post season at all.

Minnesota appears to be the unluckiest. This is probably due to their league-leading run defense, but they didn't have the wins to show for it.

Notice Pittsburgh's expected win number--10.24. They played well enough this year to win 10 games but, according to most analysts "collapsed" and didn't make the playoffs a year after winning the Super Bowl. But their regular season record last year was 11-5. One could make the case that the Steelers played only slightly worse than they did last year, but just got unlucky.

Jim Mora, Jr., former coach of the Falcons, or other fired coaches might have used this to save his job. "Mr. Blank, look, we actually played well enough to win 9 or 10 games and would have made the playoffs!" But somehow I don't think that would fly, no matter how sound the math.

2 Responses to “Which teams were luckiest in 2006?”

1. Anonymous says:

"Notice Pittsburgh's expected win number--10.24. They played well enough this year to win 10 games but, according to most analysts "collapsed" and didn't make the playoffs a year after winning the Super Bowl. But their regular season record last year was 10-6."

I think their regular season record last year was 11-5.

2. Brian Burke says:

That's true. I'll make the correction in the post.