Ever since Donald Trump has risen to the top of the polls, Republican strategists have questioned whether those polls might be overestimating his support.
There is evidence to support that theory. …
The public polls can be misleading if nonvoting adults have substantially different views from primary voters. Usually, the difference isn’t huge. But some analysts have argued that Mr. Trump’s celebrity might give him an unusual advantage among irregular voters, who might not pay much attention to political news.
The candidates’ campaigns, for whom more accurate results really matter, have moved to a different approach to polling: They draw their sample from voter registration files, which contain information on voting history. That gives campaigns a powerful tool for examining the likely electorate. CONT.
Nate Cohn, New York Times