Silver's predictions of the election outcome took much of the shine off the statistician-pollster-guru, and no amount of statistical spin ("we were expressing our confidence that the unpredictable wouldn't happen, but we left open the possibility of the unpredictable!") can restore it to its former glory, but this Fivethirtyeight explainer on the polls that show a huge variance in Trump's approval and disapproval ratings is the kind of detailed analysis that is mostly light, with little heat.
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Oh, just the 7th largest gathering of humans in history happened last week.
Five million of the most patient humans in the world -- Cubs fans -- descended on Chicago's lakefront last week to celebrate a victory that was against all odds. But win they did, ending the longest World Series drought in baseball history -- 108 years -- and the lifting of the Billy Goat Curse. Friday's event was the 7th largest get-together in human history, about a million shy of the 2015 papal visit to the Philippines. The rest of us can keep it simple and get a glimpse of the Cubs on The Tonight Show Monday. The event in Grant Park turned out to be a pretty tame party for Chicago, when you consider the things fans have done over the years to try to lift the curse.
Billy Goat Tavern owner Billy Sianis' pet goat Murphy was lacking in hygiene and was thusly ejected from Wrigley Field in 1945.
But first, what is the Billy Goat Curse? In 1945, Billy Goat Tavern owner Billy Sianis and his goat were ejected from Wrigley Field during Game 4 of the Cubs first World Series since 1908. Apparently the goat's odor was offensive, Sianis was offended and enraged, and legend has it that he declared, "Them Cubs, they ain't gonna win no more." The Cubs lost the game that day and haven't even been a contender in another World Series, let alone champions, in the 108 years since. Until last week. Read the rest
The election is next week. And, with that in mind, Salon's Paul Campos has posted a helpful reminder explaining what the statistics at the fivethirtyeight blog actually mean (and what they don't).
In particular, you have to remember that, while Nate Silver gives President Obama a 77.4 percent chance of winning the presidential election, that's not the same thing as saying that Obama is going to win.
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Suppose a weather forecasting model predicts that the chance of rain in Chicago tomorrow is 75 percent. How do we determine if the model produces accurate assessments of probabilities? After all, the weather in Chicago tomorrow, just like next week’s presidential election, is a “one-off event,” and after the event the probability that it rained will be either 100 percent or 0 percent. (Indeed, all events that feature any degree of uncertainty are one-off events – or to put it another way, if an event has no unique characteristics it also features no uncertainties).
The answer is, the model’s accuracy can be assessed retrospectively over a statistically significant range of cases, by noting how accurate its probabilistic estimates are. If, for example, this particular weather forecasting model predicted a 75 percent chance of rain on 100 separate days over the previous decade, and it rained on 75 of those days, then we can estimate the model’s accuracy in this regard as 100 percent. This does not mean the model was “wrong” on those days when it didn’t rain, any more than it will mean Silver’s model is “wrong” if Romney were to win next week.