But some pollsters, especially the relatively few who conduct surveys in battleground states, are still grappling with the same problems that plagued those polls four years ago. In fact, most pollsters believe that, on balance, state polls are overstating the scale of Biden’s advantage…

Pollsters are looking for answers. One of the major takeaways of the American Association for Public Opinion Research’s post-2016 autopsy was that state polls that didn’t weight, or adjust, their samples to include more white voters who hadn’t graduated college missed a key element of Trump’s coalition. In previous elections, the differences in white voters’ preferences along educational lines were smaller, but began to grow last decade and accelerated with Trump on the ballot in 2016.

“Before 2014, it wasn’t that big of a deal because the reality is non-college white voters and college-educated white voters — the distinction between the two wasn’t as dramatic,” said Democratic pollster Jefrey Pollock. “But starting with 2014, that began to cleave a lot and is now obviously humongous.”

GOP pollster Glen Bolger said he believes a combination of pollsters’ inability to get the right educational mix and to convince potential Trump voters to respond and answer truthfully to phone polls is pointing their surveys in a slight Democratic direction.