Posted by
Always To The Right on Monday, November 03, 2008 12:58:00 PM
For a simple reason: They oversample Democrats, and are even more likely to do so this year thanks to enthusiasm among The One’s cultists. Per Geraghty,
77 percent of Obama’s supporters say they’re willing to spend 10
minutes answering an exit poll questionnaire versus just 64 percent of
McCain’s. No matter what’s happening on the ground, then, expect The
One to have a large-ish lead when the data finally drops at 5 p.m.
tomorrow. If he doesn’t, things could get interesting.
Even the networks don’t trust them in isolation anymore:
[T]he networks now follow strict rules that govern
projections, examining not only exit poll data but actual vote
tabulation and turnout information. NBC — which keeps its decision desk
isolated from the calls made by competing networks — will only call a
winner once its statisticians conclude that the chance of an error is
less than 1 in 200. And no calls will be made until all the polls have
closed in a state…
[E]xit polls are designed to provide a demographic portrait of
voters, not to predict the winner of a close race. The early waves of
data can be especially misleading because they do not necessarily
reflect an accurate sample of the electorate.
This year, there’s another factor to take into account: the huge
surge in early voting. To get a measurement of those voters,
Edison/Mitofsky has been doing an extensive telephone survey in the
last week, focusing on the 18 states with the highest concentration of
absentee and early voting.
For all the precautions, the networks’ decision desks will still be
analyzing the exit poll with some wariness. In both 2004 and 2006, the
polls overstated the Democratic vote in many states. Because of that,
Fox News stopped relying on the data halfway through election night in
2006, declaring it unreliable.
A similar problem cropped up during this year’s primaries, when exit polls often showed a greater lead for Sen. Barack Obama than the actual vote, decision desk directors said.