How likely is it that the polls are wrong?

[courseofhistory]

at 04:34 PM ET, 10/30/2012

How likely is it that the polls are wrong?

By Jonathan Bernstein

Could the polls be wrong? Yup. But they probably aren’t.

Remember, the state of play, at least until Sandy shut down a lot of polling, is that the national vote is basically tied (with Mitt Romney possibly having a very narrow edge) while Barack Obama appears to have a 2-3 percentage point electoral college advantage. What that means is that in a tied race nationally, Romney would have to win basically every close swing state to win. If the polls are correct and nothing changes between now and Tuesday, the chances for an Obama victory are good.
How likely is it that the polls are wrong?

They could be wrong, no question about it. For example: many polls still find better enthusiasm among Republicans than Democrats. This could yield a large turnout advantage for Romney, one which most polls are not picking up, but which Gallup’s likely voters screen has been projecting. If Gallup’s 5 percentage point difference between registered and likely voters is correct, then polls with looser likely voter screens might be harsher to Romney than the actual electorate. That’s one possibility. Another is the possibility that undecided voters will break sharply for Romney. The evidence suggests that “how the undecidedss ‘break’ may not be consequential in this election. But could it be consequential? Sure.

One more possibility: That old chestnut, the Bradley Effect — that is, people who don’t want to admit to pollsters that they don’t want to vote for an African American candidate. No, that didn’t show up in 2008. Could it show up this time? It might.

But the polls could also be wrong in ways that favor Democrats

http://www.washingtonpost.com/blogs/plum-line/post/how-likely-is-it-that-the-polls-are-wrong/2012/10/30/8dbdcc9a-22c4-11e2-92f8-7f9c4daf276a_blog.html

[DemocratSinceBirth]

1. Duh

When virtually every poll's results lie well within its margin of error how is it possible to make any kind of statement regarding its validity

-michael19

In probability theory, the law of large numbers (LLN) is a theorem that describes the result of performing the same experiment a large number of times. According to the law, the average of the results obtained from a large number of trials should be close to the expected value, and will tend to become closer as more trials are performed.

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