kalikshama -> RE: The parallel universe where Mitt Romney leads all polls (10/2/2012 7:17:19 AM)
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Poll Averages Have No History of Consistent Partisan Bias By NATE SILVER Presidential elections are high-stakes affairs. So perhaps it is no surprise that when supporters of one candidate do not like the message they are hearing from the polls they tend to blame the messenger. In 2004, Democratic Web sites were convinced that the polls were biased toward George W. Bush, asserting that they showed an implausible gain in the number of voters identifying as Republicans. But in fact, the polls were very near the actual result. Mr. Bush defeated John Kerry by 2.5 percentage points, close to (in fact just slightly better than) the 1- or 2-point lead that he had on average in the final polls. Exit polls that year found an equal number of voters describing themselves as Democrats and Republicans, also close to what the polls had predicted. Since President Obama gained ground in the polls after the Democrats’ convention, it has been the Republicans’ turn to make the same accusations. Some have said that the polls are “oversampling” Democrats and producing results that are biased in Mr. Obama’s favor. One Web site, unskewedpolls.com, contends that even Fox News is part of the racket in what it says is a “trend of skewed polls that oversample Democratic voters to produce results favorable for the president.” The criticisms are largely unsound, especially when couched in terms like “oversampling,” which implies that pollsters are deliberately rigging their samples. But pollsters, at least if they are following the industry’s standard guidelines, do not choose how many Democrats, Republicans or independent voters to put into their samples — any more than they choose the number of voters for Mr. Obama or Mitt Romney. Instead, this is determined by the responses of the voters that they reach after calling random numbers from telephone directories or registered voter lists. Pollsters will re-weight their numbers if the demographics of their sample diverge from Census Bureau data. For instance, it is typically more challenging to get younger voters on the phone, so most pollsters weight their samples by age to remedy this problem. Read more: http://fivethirtyeight.blogs.nytimes.com/2012/09/29/poll-averages-have-no-history-of-consistent-partisan-bias/
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