From Bloomberg Megan McArdle writes Pollsters Are Worse Than Ever
I won’t opine on What It All Means. But let’s talk about the surprise factor: The polls were wrong. And as Nate Silver points out, this seems to be a troubling trend, not just in Britain, but around the world. The polls on the Scottish independence referendum were way off. So were the ones that missed the Republican sweep in the 2014 midterms. Israel’s pre-election and exit polls both missed Likud’s solid victory.
We’ve always known that polls had problems. You can get very different answers depending on how you ask the question, as “Yes, Prime Minister” effectively dramatized. Sampling problems arise when people who don’t get chosen for the poll, or refuse to respond, are systematically different from the rest of the population. (This is how the infamous “Dewey Defeats Truman” headline happened.) Even with problems, however, polls remain useful — as long as you keep those problems in mind.
I’ve seen a lot written today about how this shows the need to fix polling. I’ve seen few people asking what seems like the more pertinent question: What if polls can’t be fixed?
Glenn Reynolds comments on the article at Instapundit that demonization of the right by the dominance of media and polling organizations may solicit false polling data. This would lead to distorted feedback loop that makes news media even less accurate: creating polls that are distorted by an atmosphere created by the media that conducts and reports the poll.
I would contend that polls too often direct questions to a short term outcome dismissing reasons underlying the response. Racial and gender stereotypes weigh too heavy in analysis when income and other profiles tell a better and more accurate story.
more on this line of thought from National Review’s John Fund, Conservative Voters Give Pollsters Politically Correct Answers . . . and Then They Vote
Silver came up with various explanations for the errors, noting first of all that voters are becoming harder to contact, so pollsters rely less on direct contact and more on online questionnaires. Some of those online polls abandon probability sampling, the bedrock of polling methodology. In addition, he also observed that “some pollsters have been caught withholding results when they differ from other surveys, ‘herding’ toward a false consensus about a race instead of behaving independently.”
I’m not sure that’s the case, but even if it is, the problem of people giving politically correct responses to pollsters isn’t confined to Britain. As Nate Silver concluded, “Polls, in the U.K. and in other places around the world, appear to be getting worse as it becomes more challenging to contact a representative sample of voters.”
Read more at: http://www.nationalreview.com/article/418172/conservative-voters-give-pollsters-politically-correct-answers-and-then-they-vote