General election 2024

Method

About our method

The way we calculate our recommended tactical vote is designed to be open, rules-based and easy to follow. Tactical voting is ultimately about coordination between thousands of voters, which means that it is important not to produce unexpected results. Using the same rules to calculate every seat also helps to avoid any possible bias in the recommendations.

The aim is to find the 'correct' tactical vote for every seat – that is, the party that will either win or come second to the Tories.

The basic rules

1. Look at the result of the most recent general election in the constituency.

2. In seats currently held by a progressive party, recommend a vote for that party.

3. In Tory-held seats, recommend a vote for the second-place party from the previous election.

4. If progressive parties are in both first and second place, we make no recommendation.

Adjustments for boundary changes

For the 2024 election, many constituencies have changed, being split or combined into new boundaries.

To adjust for this, we have calculated 'notional' 2019 results: an estimated result for this constituency if it had its new boundaries in 2019. Here is the process:

1. We begin from a percentage overlap (by population) between the old and new constituency.

2. For each constituency that makes up part of the new constituency, we multiply the 2019 result by that overlap percentage.

3. Finally, sum the 2019 results by party to get the notional result.

Here is a worked example to illustrate this:

Croydon West is a new constituency. By population, it is made up of 74% of the old Croydon North, 13% of Croydon Central and 13% of Croydon South.

Therefore, each party's vote total for Croydon North is multiplied by 0.74, for Croydon Central by 0.13 and by Croydon South by 0.13. These are then added up by party. This gives the notional 2019 Croydon West result.

Special cases

Some seats are a bit more complicated, so we have some rarer rules to handle these special cases.

1. In seats from rule 4 where the Tories are in third place but have a high vote, so a divided opposition could let them 'come through the middle', we recommend voting for the incumbent.

2. Where a seat has been won in a byelection, we recommend a vote for the byelection winner. (However, second-place finishes in byelections are not taken into account.)

3. In seats where the Tories do not stand, we aim to defeat the 'Tory-aligned' party. For example, in Northern Ireland, this means defeating the DUP because they propped up the 2017-19 Tory minority government.

4. We also consider the Reform Party (formerly the Brexit Party) 'Tory-aligned' as above, after their pact with the Tories in 2019. Where they are relevant we also aim to defeat them.

5. In the Speaker's seat we make no recommendation, as mainstream parties do not stand in this seat.

6. Where a seat is contested by an independent candidate who was formerly a sitting MP, we will consider their record of votes in that seat only (not any other seat if they have switched constituencies). The same number of votes will remain attributed to their former party.

7. Green rebalancing rule: As tactical voting disadvantages small parties such as the Greens overall, if there is a contest between two progressive parties with no risk of a Tory win, and one of the two is the Greens, we call for a vote for the Greens.

8. 'Not needed' rule: Where a progressive party is far ahead in a constituency (over 30%), we have marked it to show that we do not believe tactical voting is needed here this time.

When we are not sure

Sometimes particular seats are unusual - for example when the numbers are 'too close to call' (within 2%), when prominent politicians stand as independents or where there has been a defection from one party to another. In these seats we may say 'Not Sure'.

We may also switch a recommendation to a special status, 'Withdrawn', if our recommendation appears incorrect from polling (only if consistently in multiple different polls) or, rarely, to avoid a situation where different tactical voting websites disagree on a seat.

Our bottom line 'golden rule' is that we will not manually change a recommendation to a different recommendation - only from a positive recommendation to 'Not Sure' or 'Withdrawn'. This is to protect the site from pressure that can form around particular candidates but turn out to be an incorrect tactical vote.

If you believe we have made a mistake, please contact us at feedback@tactical.vote, but the potential result is not a change to your preferred candidate, only a withdrawal of our current recommendation.

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