N.F.L rankings

I didn't get a chance last year to do my N.F.L. rankings, but here they are far this year. I made a slight tweak and used a logistic function to rate each win. A small point differential resulted in a half-win to each time. A large point differential resulted in one team getting much closer to a win (nearly 1) and the other getting a loss (closer to 0). However, with a logistic function, the differential does not result in a linear change. Basically, I set it up so that anything beyond a two-possession game -- for example, one team wins by 16 points -- is above a 0.90 for the winning team. Running up the score further pushes the win closer to a 1 in an ever slower fashion.

The next step was to use these adjusted results to do a strength-of-schedule adjustment.

Here is my logistic function:

$win=\left\{\begin{array}{l}0\text{ if differential≤3.5}\\ \frac{1}{1+e^{-(dif\mathrm{f-}3.5)/5}}\end{array}\right.$

And here are my rankings:



The link to download it. No real surprises, except that the Ravens are ranked in my method ahead of the Bengals, Colts, and Steelers.

My wild-card round predictions: Ravens over Steelers (the only "surprise"), Colts over Bengals, Cowboys over Lions, Cardinals over Panthers.

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Update, 1/5/2015: Got the Ravens, Colts, and Cowboys right. Got the Panthers wrong (although this should have been the one I was the most confident about). Score: 3/4.

Next predictions for the divisional playoffs, using the unrevised list above: Patriots over Ravens, Broncos over Colts, Packers over Cowboys, Seahawks over Panthers.

Update, 1/13/2015: Got the Patriots, Packers, and Seahawks right. Got the Colts wrong. Score: 3/4.

Next predictions: Seahawks over Packers, Patriots over Colts.

Update: 1/21/2015: Got both right. Score: 2/2.

Next predictions: Seahawks over Patriots in the Superbowl.

Update: Wrong Superbowl prediction. 0/1.

Total score: 8/11, or 73%.