The AAPOR report on 2016 “polling failure”

[Mr. Morden]

Anyone taken a look at this new report yet?  There are some summaries here:

http://www.politico.com/story/2017/05/04/2016-election-pollsters-react-237975

https://www.washingtonpost.com/politics/were-the-polls-way-off-in-2016-a-new-report-offers-a-mixed-answer/2017/05/04/a80440a0-30d6-11e7-9534-00e4656c22aa_story.html

Sounds like they’re saying that the polling problems of last year came about not because of any kind of “Shy Trump voter” effect, in the sense that people were lying to pollsters about their voting intentions, but because of sample selection problems.  (Which is exactly what I was saying months ago.)

Specifically, the issue was that national pollsters were more likely to weight by education level than state pollsters, which was a problem for polling in the Rust Belt, where there was an especially high undercount of voters without a college degree:

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[Mr. Morden]

Isn't demographic weighting itself a pretty shoddy practice? It is essentially increasing the effective margin of error of the poll to avoid ugly-looking crosstabs.

If you don't do any demographic weighting then you just get complete junk, since some demographic groups are markedly more likely to respond to polls than others.

[Mr. Morden]

And I don't think that this is a new issue.

I guess the "missing" uneducated voters have not voted homogeneously before why one couldn't see the results of this issue. The thing is that in 2016 they did.

Yes, that is the issue.  There wasn't that much of an education gap between the parties as recently as the 2012 presidential election.  So if your polling screwed up the educational weighting or didn't do it at all, then it wasn't likely to impact the topline number.  But since 2016 saw a big education gap between the parties, not doing any educational weighting now creates a big bias.