We have chosen not to link the Reform Party to the Brexit Party vote of 2019. It is worth noting that this is a model, and like every model, it has its limitations and assumptions. We have also split the model up to treat Scotland and Wales separately, as they have single-nation parties (the SNP and Plaid Cymru).

We then adjust this threshold based on how much a party’s vote share has historically fluctuated in each seat, both at a parliamentary level and a local council level. This is based on British Election Study figures showing 29-35 per cent of voters chose a party different to the one that they had previously voted for at the most recent general election. Firstly, we recognise that weak voters can be reinterpreted as swing voters, and so rather than applying a uniform threshold of 20 per cent to split voters into strong and weak based on seat turnout, we have created separate thresholds for each party in each seat. The New Statesman’s model makes several amendments to the STM, however. This means the model takes incumbency into account, as parties with large proportions of strong supporters in a seat will lose a smaller number of votes in that seat than under the standard model of UNS. Strong voters are less prone to shifting their support than weak voters. Instead, they fall multiplicatively, with those losses split among the advancing parties in proportion to their national gains.Īnother modification the STM makes is dividing the parties up into strong and weak voters. Parties that fall, say, four points nationally, won’t necessarily fall four points locally. The advantage of this model over the simple uniform national swing (UNS), which is often used elsewhere, is that parties with a declining vote share nationally cannot get negative votes in any particular seat, or gain votes to more than 100 per cent of the total. The engine of the calculator is based on the strong transition model (STM) of predicting UK elections, created by Martin Baxter of Electoral Calculus. An election calculator is not a flawless way to predict an election, but a number of those online today have form for getting the results roughly right.īritain Predicts recognises that the country doesn’t often vote or swing as one, and that there are people in some constituencies who are more susceptible to changing their vote than those living elsewhere.

Strong together uk election