Source: New York Times
A year after polls broadly overestimated Hillary Clinton’s strength in the decisive Rust Belt battleground states, top pollsters and analysts across the survey industry have reached a broad near-consensus on many of the causes of error in the 2016 presidential election.
But so far, public pollsters — typically run by news outlets and colleges — have not changed much about their approach. Few if any of the public pollsters that conducted surveys ahead of Tuesday’s elections for governor in Virginia and New Jersey appear to have adopted significant methodological changes intended to better represent the rural, less-educated white voters who pollsters believe were underrepresented in pre-election surveys.
On the other hand, private pollsters — typically employed by campaigns and parties — have already begun to make changes. This is especially true among Democrats stunned by Donald J. Trump’s upset victory, but Republicans are making changes as well. The adjustments are already playing out in Virginia, where pollsters will have one of their first chances to put postelection shifts to the test.
“Virginia is an important test case for pollsters to try new methods, given some of the issues with 2016 state-level polling,” said Nick Gourevitch, a Democratic pollster at Global Strategy Group, a firm working with the Democratic Governors’ Association to use the Virginia election to calibrate postelection changes and experiment with new approaches.
Nearly all of the private pollsters interviewed for this article have, at minimum, begun to do something about education. There is widespread agreement that the industry failed to properly represent less-educated white voters, and that this was part of why last year’s polls were too favorable to Democrats. It’s likely to remain a big issue, at least as long as white voters split so decisively on educational lines. The postelection report of the American Association for Public Opinion Research, the nation’s leading polling association, reached a similar conclusion.
One possible fix is to weight by education, which would give more or less weight to certain respondents to ensure that less-educated voters represent the appropriate share of the poll’s final estimate. For many public polls, weighting by education would make a big difference. It could move an otherwise lightly weighted poll by as much as four percentage points toward the Republicans in the Virginia governor’s race, for example, based on an analysis of the most recent Upshot/Siena College poll. With the Democrat, Ralph Northam, holding a modest lead in most polls, the difference could be enough to flip several surveys in the state.