Member Since: 10/9/2009
Posts: 6,108
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Here's a good article about how the exit polls work. It also states that the some exit poll info may leak on Twitter or something before the networks confirm. Just ignore them. We should be getting the first exit polls once the polls closes in the east later tonight.
Quote:
If you care about politics and spend a fair amount of time online, odds are good that sometime between 5 p.m. and 7:30 p.m. Eastern time on Tuesday, you will encounter someone sharing leaked "exit poll" numbers that purport to tell you who will win various battleground states.
It may be tempting to assume the numbers will tell you who is going to win the presidential election.
They probably won't.
Hard as it may be, you should try to ignore them, at least until the polls close. And even then, take the underlying vote estimates with big grains of salt.
But let's first stipulate that once weighted to match the actual outcome, exit polls are an incredibly valuable resource. Conducted every two years by Edison Research for the National Election Pool partnership of ABC, CBS, CNN, Fox, NBC and the Associated Press, the exit polls are easily the best measure available of who voted for each candidate and why.
So it was for good reason that many political junkies expressed disappointment when news spread that the National Election Pool will only conduct complete exit polls in 31 states this year, down from the usual 50. In recent years, these surveys have become far more expensive, as the rise in early voting created the need for parallel telephone surveys to measure the preferences of early voters.
But as tools to predict the outcome of close races just before the polls close, they are blunt instruments at best. Here's why:
First, an exit poll is just a survey. Like other polls, it is subject to random sampling error, so differences of a few percentage points between the candidates in any given state sample are not terribly meaningful.
Second, the networks almost never "call" truly competitive races on exit poll results alone. The decision desk analysts require very high statistical confidence (at least 99.5 percent) before they will consider calling a winner (the ordinary "margin of error" on pre-election polls typically uses a 95 percent confidence level). They usually only achieve that confidence for relatively close races after the exit pollsters obtain the actual vote results from the randomly selected precincts at which interviews were completed (and from other larger random samples of precincts) and combine all of the data into some very sophisticated statistical models.
Even then, if the models project that the leading candidates are separated by just a few percentage points, as pre-election polls suggest they will be in all of the key battleground states, the networks will usually wait until nearly all votes are counted to project a winner.
Read more at: http://www.huffingtonpost.com/2012/1...n_2038617.html
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