IA-Selzer: Trump +7

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And the trend of 2020 polls almost exactly matching their 2016 counterparts continues apace...

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And the trend of 2020 polls almost exactly matching their 2016 counterparts continues apace...

This is outright false

DMR
Marquette
Morning Call
Quinnipiac in PA
NYT/Siena in PA (at least so far)
Marist in NC

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This shows why weighting by education won't solve anything. The root problem is that Biden supporters are eager to answer polls, while Trump supporters hate the media and won't answer polls or will lie instead. Of course, this effect varies state by state (and was non-existent for Obama vs Romney). The only way to fix this is to weight by Trump support, but of course that's what you're trying to measure in the first place.

I wonder if one reason Selzer is more successful is that in Iowa specifically there is a higher tendency for Trump supporters to answer a DMR poll honestly because of its reputation. Same but to a lesser extent with Marquette in Wisconsin.