In 2016, the polls were more right than wrong. The final national surveys had Hillary Clinton ahead of Donald Trump ahead by an average of 3 points; Clinton ended up winning the popular vote by 2 points. But some state polling missed the mark badly, especially in Midwest and Rust Belt states. Trump narrowly carried Michigan, Pennsylvania and Wisconsin, where some long-respected state polls had shown Clinton with a narrow lead.
One of the most prominent explanations for 2016’s polling whiffs was that these state polls surveyed more college-educated voters than the actual share of college-educated voters in the population. As a result, they were missing participants with lower education levels.
But last fall, NBC News’ state polling partner — Marist College’s Institute for Public Opinion — conducted an experiment with Edison Research by polling Kentucky’s competitive gubernatorial race and reached a different conclusion: Education appears to be a piece of a bigger geographic puzzle with how pollsters build their samples. CONT.
Mark Murray & Carrie Dann, NBC News
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