Sunday, December 12, 2010

Betting on the Weather Is a Sign You Have a Problem

It's going to be snowy and cold at Soldier Field this afternoon -- a first for Chicago in December, I'm sure. Someone out there in PatriotInternetland has let it be known New England is 9-0 in games played when it snowed during Bill Belichick's tenure as coach.

That statistic, while mildly interesting, has no value as a forecasting tool for today's Pats-Bears game. It is another example of how people adore confusing correlation with causation.

The Pats have won all their snow games. Does this mean that they play better when it snows? Or does it mean that snow games are a statistically insignificant subset of the meaningful fact that the Pats have been a spectacularly successful team since 2001 in all conditions, rain or shine, warm, cold or indoors? If picked the first possible answer, I hope someone else is investing your money for you.

Apply a little logic to the problem. Like almost teams no matter what their winning percentage, the Pats of the past decade have had a better record at home than on the road. Like many championship teams in all sports, the Pats under Belichick have been strong closers, becoming particularly hard to beat after Thanksgiving Day. It's pretty rare to go through a December in New England without at least one snowstorm. And as in 2010, the Pats also often have a December road trip to Buffalo, where while the weather may be frightful, the Bills have always been their special little friends.

So the Pats' perfect record on Snow Days is not a special case, it's a distillation of other trends, most particularly their home field record. It is the flip side of a stat that lasted for decades, the former fact that Tampa Bay had never won a game played outdoors when the temperature was below 35 degrees. That record existed because the Bucs didn't win many games when it was nice out, either. Once Tampa Bay became a good team in the late '90s, the record eventually went away.

The weather in Chicago will make playing the game an unpleasant experience for both clubs -- although it certainly won't be an unfamiliar experience for either one. But aside from how snow and wind might make the ball take even funnier bounces than usual, it won't affect which team has the even more unpleasant experience of losing.


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