Tactical Voting Parameters

Revised 27-Jun-2024

Our user-defined prediction tool allows users to manually enter tactical voting parameters, letting you control the extent of tactical voting for your prediction. This feature works on the basis of Electoral Calculus' tactical voting model.

Our tactical voting model

The model's parameters are based on a polling we have conducted, usually prior to each general election. We asked supporters of each of the main parties how they intend to vote if their first preference is likely to place third or below in their constituency.

Example

This is how Labour supporters in England said they would vote if Labour were unlikely to win in their seat for the 2024 general election:

54% of Labour supporters would not vote tactically even if Labour were unlikely to win the seat. But 24% would switch to the Lib Dems, and 22% would switch to the Greens, if either of those parties were competitive. No Labour supporter would switch to the Conservatives or Reform.

Therefore, in seats where the Lib Dems are competitive but Labour are not, our model will allocate 24% of Labour's support to the Lib Dems. In seats where the Greens are competitive but Labour are not, 22% of Labour's support will be allocated to the Greens.

Each party's supporters will engage in tactical voting to different levels, and in different directions. In 2024, there was a lot of anti-Conservative tactical voting between Labour, Lib Dem and Green party supporters, but less so between Conservative and Reform voters.

Tactical voting patterns in Wales and Scotland, and at other elections, are different.

See the full details on our tactical voting model for the 2024 general election.

Tactical Voting Input Parameters

If you enter 100% for a given party, our tactical voting model will be applied in full effect. This means that in, say, seats where Labour are not competitive, but the Lib Dems are, the full amount of tactical voting that our model predicts will be applied to the Lib Dem vote share.

If you enter 50% for a party, the model will be applied to 50% effect. This means that the tactical voting model will still be applied, but with 50% less tactical voting. In numerical terms, Labour supporters' tactical voting under these conditions would look like this:

If you enter 0% for a party, it assumes no tactical voting, so none of their supporters' votes will be allocated to other parties.

Tactical voting input parameters apply to each party individually. This allows you to set different levels of tactical voting for different parties. For example, if you think that lots of Labour, Liberal Democrat and Green supporters will vote tactically, but Conservative and Reform supporters won't vote tactically, you could enter something like the following:

Tactical preferences

Voters who vote tactically do not all pick the same destination for their tactical vote. It depends on which other parties they support to some extent, and also on the characteristics of the seat. For example, non-Green voters are unlikely to vote Green tactically unless the Green party is competitive in that particular seat.

The trends of tactical preferences for the 2024 general election are estimated as follows:

• Tactical Conservative supporters tend to vote for Reform
• Tactical Labour supporters tend to vote for the Liberal Democrats and the Greens
• Tactical Lib Dem supporters tend to vote for Labour and the Greens
• Tactical Reform supporters tend to vote for the Conservatives
• Tactical Green party supporters tend to vote for Labour or the Liberal Democrats
• In Scotland, there is pro-Union tactical voting between Labour and the Liberal Democrats, and pro-Independence tactical voting by Greens to the SNP