How accurate will those polls be?
by David Atkins
With the state-by-state polls showing narrow but substantial leads for Obama, conservatives in the media have taken to attacking poll averages as unreliable. But how unreliable might they be? John Sides at The Monkey Cage has the details:
How trustworthy are this year’s presidential polls? On Monday, November 5, will they be able to tell us who is likely to win the election? We’ll know soon enough, but in the meantime the historical record provides some important context. This record suggests three things:
1) The polls have been fairly accurate. (Adverbs are always a bit subjective, so see what you think after you read the post.)
2) To the extent that they miss, they do so by over-estimating the frontunner’s vote.
3) The reason they miss is not because of late movement among the undecideds but because of “no-show” voters who tells pollsters that they will vote but then don’t.
They don’t miss much:
In very close elections, the polls are still quite close to the actual outcome—missing by 1-2 points at most. They slightly underestimated Gore’s share of the vote, for example. Of course, in a close election, 1-2 points is consequential. But it’s not reasonable to expect polls to call very close elections right on the nose…
The attack on polling itself is just another Republican attack on science that conflicts with their preferred worldview. They’ve filled their supporters’ heads with the line that all the pollsters but Rasmussen are in the bag for Obama, and that Democrats are engaged in invisible, massive voter fraud. So rather than shatter their illusions, a rejected Obama lead in the polls will become a rejected Obama margin on election day, with a different conspiracy theory narrative neatly aligned to fit the event.
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