Huffpost — Late Shift In Key States Helped Elect Trump, Report Finds

In the age of Trump

HuffPost — Late Shift In Key States Helped Elect Trump, Report Finds Voters who made up their minds in the final week helped to throw off swing state polls.

WHAT HAPPENED WITH 2016 ELECTION POLLING? - An American Association for Public Opinion Research (AAPOR) report, released Thursday, digs into the performance of last year’s surveys. HuffPollster: “National polls, which largely predicted a modest win for Hillary Clinton in the popular vote, weren’t too far off. But state polling missed the mark significantly, and often uniformly, leaving much of the public feeling utterly blindsided by Donald Trump’s victory...A late shift in key swing states and a failure to correct for the underrepresentation of less-educated voters played out against the backdrop of a close race that saw different winners in the Electoral College and the popular vote. The resulting errors were fundamentally worsened by pollsters, forecasters, and aggregators who were either overconfident in their results, or unable to convey a proper level of uncertainty to the public.” [HuffPost, full report, additional coverage from WashPost, Politico, AP]

What went wrong, according to the report: More from HuffPollster: “In Florida, Michigan, Pennsylvania, and Wisconsin, between 11 percent and 15 percent of voters said they made up their minds in the final week of the campaign. Late deciders in those states, several of which saw a last-minute surge in attention from the campaigns, broke heavily for Trump….[B]etter-educated voters were likely to support Clinton. That presented a problem for some pollsters, because highly educated voters are also more likely to answer polls….While many pollsters weight their surveys to correctly reflect Americans’ educational backgrounds, some, especially at the state level, did not.”

What we still don’t know: “The impact of other potential factors is less clear, according to the report. The report sheds no light, for example, on the effect of FBI Director James Comey’s letter to Congress….Similarly, while likely voter models ? pollsters’ efforts to determine which of the people they talk to will actually show up on Election Day ? presumably played a role, much of the data that would help measure the exact effect isn’t yet available.”

What didn’t go wrong: “The study found no evidence of a consistent bias toward one party in recent polling. While Trump was underestimated last year, Democrats Barack Obama and Al Gore also saw their standing underestimated in election polling. ‘The trend lines for both national polls and state-level polls show that ? for any given election ? whether the polls tend to miss in the Republican direction or the Democratic direction is tantamount to a coin flip,’ the report’s authors write.”

What to know for next time: “Pollsters who didn’t already account for educational levels can take more care to do so. But there’s no reason why future elections won’t also see last-minute shifts in swing states, or an Electoral College result that doesn’t reflect that popular vote…. panelists on Thursday suggested that pollsters, aggregators and journalists should spend more time emphasizing that surveys represent only a snapshot of public opinion at the time that they’re taken, and that the uncertainty surrounding polling goes far beyond the stated margin of error.”