Polling by YouGov suggests a surge in support for the Green party across the country following the Gorton and Denton byelection. According to the poll, Zack Polanski’s party now has a national vote share of 21%, leapfrogging the Labour party. The Greens now sit within the margin of error behind Reform’s 23%.
In light of this result, some have claimed that the Green party’s byelection victory has boosted its national polling by making it look like a party that can win in an election. This is a version of what is known among political scientists as the bandwagon effect. The idea is that voters jump on the bandwagon of parties that are very popular with other voters.
But it’s not necessarily the case that voters are now thinking of going Green just because the Greens won in the byelection. Coverage of byelection results has a longstanding tendency to focus too much on which party wins and not enough on trends in vote shares.
