Four days before Election Day, we are awash in polls, which tell us … what? Former Vice President Joe Biden appears set to win the presidency, but the polls in key states could be wrong. Again. That, at least, is the fear of some voters, and for others, hope. 

But there is reason for more confidence about polling this time. For one, pollsters have adjusted how they sample and consider important subgroups.

“There’s more weighting for educational level this time,” says Terry Madonna, director of the Franklin and Marshall College Poll in Pennsylvania. His latest poll of that state has Mr. Biden ahead by 6 percentage points. 

Indeed, the “diploma divide” has only grown, with college grads increasingly voting Democratic, as my colleagues Simon Montlake and Story Hinckley write.  

Pennsylvania is crucial, as one of the three “blue wall” states that President Donald Trump won unexpectedly last time. But in many ways, 2020 is not 2016. President Trump is running as an incumbent. The polls have been remarkably stable. Undecided voters are relatively few. 

But what about “shy voters,” those unwilling to tell a pollster what they really think? That phenomenon may help Mr. Biden, too, not just Mr. Trump, notes analyst David Wasserman of the nonpartisan Cook Political Report. 

More important, voters need to consider what they’re asking polls to do. 

“If the answer is to predict the future, then trust in polls is misplaced,” writes Michael Dimock, president of Pew Research Center. “But if the answer is to reveal the public’s priorities and values – and why people vote the way they do – then polls are the best tool.”