Referendum maths

Referendums are strange things. Today, there was a referendum in Hungary in which the vote was 95% in favour of the proposition presented, but the turnout was only 45%. I don't want to comment on the issue, but simply on the numbers, because it's a good illustration of how the outcome can be manipulated.

Clearly what happened was that those in favour of the proposition turned out to vote, but those against it stayed at home. Because of that, the referendum technically failed because the turnout was less than 50%. But the Hungarian Government won't let that stand in their way.

And why should they? Let's imagine a situation in which those against the proposition had been urged to go out and vote instead of stay at home. The turnout would then have been higher that 50%, and the proposition would have technically passed. That's because it is very unusal for everyone to go out and vote in any referendum or election.

I think we'd regard 85% as an exceptionally high turnout in a western democracy. A 95% majority on a 45% turnout represents 42.75% of the electorate. If the turnout had been 85% (indicating tht 15% were undecided about how to vote, or didn't care about the issue one way or the other) that would leave those opposed to the motion at 42.25% of the electorate, leaving them in a minority.

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Why do these numbers matter? Because I reckon we are likely to see almost exactly the same result in the upcoming referendum on Catalan independence.

After several monhs of uncertainty, it now appears that the referendum on Catalan independence is back on track. Only this week, President Carles Puigdemont said, "There will either be a referendum, or there will be a referendum."

When that referendum is held, those who are against independence will not turn out and vote No. They will say that the referendum is illegal and use that as a pretext to encourage people not to vote. At a guess, just as with this Hungarian referendum, some 95% of those who do vote in the Catalan independence referendum will vote Yes, but the turnout will probably be below 50%. The Spanish nationalists will say that this means only 42.75% want independence, hoping that people will believe that 57.25% don't. But that won't be true. It will be to conflate two different groups: those that don't want independence and those who can't decide or don't care about the issue one way or the other.

It's one of the fundamental flaws with referendums. Sometimes it's possible to manipulate them by encouraging non-participation rather than by getting people out to vote.