What the polls can’t tell us about the midterms

Democrats are widely favoured to win the US House and make gains in the Senate, with recent polls putting them ahead in several key states. But the article cautions that polling is uncertain and should not be treated as a reliable forecast of the election result.

Polls can miss people who are less likely to respond, including younger and less politically engaged voters, and statistical adjustments cannot fully correct for those gaps. Pollsters also conducted fewer late-cycle surveys than usual, while close races in rural states such as Alaska, Maine and Iowa can be harder to measure. Turnout and a possible Republican response to fears of Democratic control could also change the outcome.