“in 2016: Trump beat his polls by just a few points in just a few states. The presidential polls were, simply, not that off. State-level polling was less accurate, although as editor-in-chief Nate Silver wrote after the election, it was “still within the ‘normal’ range of accuracy.”
That doesn’t mean there weren’t plenty of polling lessons to be gleaned from 2016, though. The importance of education in predicting a person’s political preferences was a big one.”
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“Nearly every pollster we talked to has made some kind of modification since the last general election. Some changes were precipitated by what happened in 2016, while others were driven by the challenges facing the polling industry, such as low response rates to phone calls and the greater cost of high-quality polling.
But one thing came up again and again in our interviews: Pollsters told us they were now weighting their samples by education, because one key takeaway from 2016 was just how important someone’s level of educational attainment was in predicting their vote.”
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“NBC News/Wall Street Journal polls are even weighted by the share of respondents from urban, suburban and rural areas. “This helps to make sure we are fully representing rural Americans,” said Horwitt, adding that it also “removes another factor which can contribute to poll-to-poll variation.”
A number of pollsters have also changed the way they recruit respondents to make sure they are reaching every pocket of the population. Courtney Kennedy, Pew Research Center’s director of survey research, explained that Pew has moved away from conducting polls by live phone calls that use random-digit dialing to reach respondents to an address-based approach in which Pew first gets in touch with respondents by snail mail to recruit them. Horwitt also told us that NBC News/Wall Street Journal no longer uses random-digit dialing; instead, they draw their samples from lists of registered voters, which allows them to “calibrate the mix of respondents between Republicans, independents and Democrats on each survey.”
Pollsters that reach respondents by phone are also relying more on cellphones.”
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“many pollsters are using a combination of approaches to reach the widest slice of voters.”