Practical tactical voting

Hi, it’s Rose! I write for Datawrapper’s blog, and after weeks of looking at election visualizations, today I’m recreating one myself.

In the weeks leading up to the U.K.’s recent general election, most voters could agree on at least one thing: They did not want another Conservative government. That had been clear for a long time. But it wasn’t necessarily clear how to vote for that outcome — depending on where you lived, there might be several viable opposition candidates, and splitting the vote could leave everyone disappointed.

The way to prevent that is tactical voting — casting your ballot for the candidate you can stomach who’s most likely to actually win. There were plenty of efforts in the U.K. to convince people to do this on an individual level, and the parties may have been tacitly involved as well, backing off the campaign in constituencies at risk of a split. So did it work in practice?

Before the election, as many as 39% of people planning to vote Liberal Democrat and 29% of those planning to vote Labour described themselves as making a tactical choice. It paid off. As this chart, based on one by Heinz Brandenburg, shows, constituencies tended to break clearly either for Labour or for the Lib Dems, with very few people wasting their vote on a losing candidate.

Surprisingly few races seem to have suffered from a straightforward failure to coordinate. In most Conservative constituencies where a more disciplined Labour–Lib Dem coalition might have won, the margin was very slim and there were thousands of Reform votes cast as well. (Though it's doubtful that many Reform voters would have been swayed to the Conservatives even then — with 14% support and only five seats in Parliament, they're pretty much the official party of the efficiency gap.)

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That's all from me for this week! Come back next Thursday for the very first Weekly Chart from our website developer Jonathan.