What we can trust 2020 election polls to tell us

As Election Day draws closer, Americans are being inundated with polls about the state of the presidential race. And, understandably, many are wondering whether polls can be trusted after Donald Trump’s surprise victory in 2016.

A better question to ask may be what, exactly, are we trusting polls to do? If the answer is to predict the future, then trust in polls is misplaced. 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.

Four years ago, Trump won the White House despite trailing in most national surveys at the time. Several factors explain this disconnect. For one thing, presidents are chosen through the Electoral College, not the popular vote, and national surveys can’t always pick up on state-level dynamics. (Nationally, surveys in 2016 were quite accurate by historical standards.) Polls in some key Midwestern battleground states overstated support for Hillary Clinton and understated support for Trump by not correcting for having too many college graduates in their samples. And undecided voters in key states appear to have swung toward Trump in the race’s final days – a shift that went unnoticed because few polls, if any, were in the field at the time.