The margins of error on the pollsters
Nate Silver, the wiz-kid behind the New York Times "Five Thirty Eight" blog, not only precisely called the outcome of the presidential race, he statistically nailed the performance of every state.
He has now analyzed the pollsters with a no-holds-barred accounting of their biases and average errors. For the record, the Herald/Times' pollster, Mason Dixon, didn't fare too well. According to Silver, it had a 5.4 percentage point average error rate in the eight statewide polls it conducted and it favored Republicans by a 2.2 percentage point margin. (We took a look at that here.)
"Polls by American Research Group and Mason-Dixon also largely missed the mark. Mason-Dixon might be given a pass since it has a decent track record over the longer term, while American Research Group has long been unreliable,'' Silver wrote.
The winner, with the most accuracy measure, was TIPP, a national tracking pollster for Investors’ Business Daily, followed by -- no surprise -- Google Consumer Surveys. Because most polling firms underestimated Mr. Obama’s performance, Silver wrote, polls like TIPP's that had what had seemed to be Democratic-leaning results had the best final outcome.