But pollsters — left, right and nonpartisan — say it is unlikely that a wellspring of overlooked voters will show up in November, for several reasons.

First, interest in the 2016 presidential campaign is at a record high. A Pew Research Center survey conducted in July showed 80 percent of registered voters have thought about the election quite a lot, a level higher than Pew has ever recorded. That suggests the vast majority of voters, even those who rarely cast votes, are making it through screens designed to weed out unlikely voters.

Second, volumes of political science research suggests that voters who tell a pollster they are unlikely to vote are telling the truth. If they don’t plan to show up on Election Day, they almost certainly won’t.

In fact, both Democrats and Republicans are coming to concrete conclusions about the types of irregular or rare voters who might be attracted to the polls to vote for Trump. Trump is likely to outperform Romney among blue collar whites in suburban and exurban areas, especially in Midwestern and Rust Belt states hit hard by the decline in manufacturing.

Pollsters are including those voters in their samples, strategists on both sides said.

“We’re not having trouble interviewing blue collar people,” Republican Ulm said. “I don’t think there’s a ton of mystery here.”