The Economist: “Whether Democrats are favored to win a majority of seats in the Senate depends on whether you trust the polls. The Economist’s aggregate of publicly available pre-election surveys puts the party ahead in 14 of the 35 Senate seats up for re-election this year. That would give the Democrats 50 senators, including the 36 seats that are not being contested this time. Among the ten most-competitive states, our poll-of-polls suggests Republicans are favored to gain a Senate seat in Nevada, but lose one in Pennsylvania.”
“But recent history suggests Democrats will underperform those numbers. In 2016-20 our aggregate of polls overestimated the share of the vote that Democratic candidates for senator and president ultimately won by an average of 2.2 percentage points across every state polled (see chart). Although pollsters updated their methods to try to iron out such errors, in 2020 the bias grew to 2.5 points. Even in 2018, when the pollsters did well on the whole, they undercounted Republican support in key states such as Ohio and Michigan.”
“The numbers now look rosiest for Democrats in the states where polls have recently been least reliable.”
