Misunderstanding AV

I have no particular view about the AV referendum. I haven’t decided which way to vote yet, but it’s not ambivalence as much as non-valence. I don’t feel strongly either way.

But weirdly, I still want to explore the arguments anyway, especially as public debate on both sides has been pretty poor.

One reason for this may be that lots of the people leading the debate don’t actually know what they’re talking about.

A confession: I have probably voted in over a hundred AV elections; I have run in AV elections, been a campaign manager for AV elections, and counted the votes in AV elections.

But I’ve also voted and run and organised several dozen Single Transferable Vote elections. I’ve even counted some small ones.

STV is not AV (though strictly speaking AV is a special case of STV). STV elections are ‘block elections’, where there’s more than one position being elected at the same time.

From the point of view of the voter, STV and AV look and feel almost identical. You get a ballot paper with a bunch of candidates and you rank them in order of preference.

What happens next is very different.

Counting STV elections is incredibly complicated because STV tries not to waste votes at all. Supporters of AV have used the term ‘wasted vote’ to refer to a vote for a small party under the current system. But in a block election, it’s also a wasted vote to vote for a popular candidate who’s going to be elected anyway. If Candidate A gets elected with 1000 votes but less-popular Candidate B gets 500 and both are elected to the block, then votes for Candidate A were only worth half of those for B.

STV works out the minimum quota of votes a candidate needs to get elected (say, in the example above it’s 500). If a candidate meets quota, they are elected and their surplus of votes are redistributed. So 1000 people voted for Candidate A, so 500 votes are ‘kept’ and the equivalent of 500 are reallocated. this is done by looking at the second preferences of all 1000 votes and transfering them across but at only half their value (because they’ve been half used already to elect Candidate A). If no candidate makes the quota, then the lowest candidate is eliminated and their votes reallocated at full value like in AV.

In effect, one person’s vote can split into several pieces, all helping different candidates get elected. You might split your vote down much smaller: if Candidate A had only got 505 votes, then transfers would only be worth one-hundredth of a vote each. And that hundredth can break down further.

If you’re confused, that’s because it’s confusing. It really is.

Big STV elections are usually counted by computer, because the maths is too fiddly. The order in which candidates is elected and eliminated becomes crucial, meaning a few votes can radically change the outcome of the election.

None of this is AV. AV is much simpler to count because there are no partial votes, no surpluses, no quota apart from 50% and only one candidate to elect. You don’t even need a calculator.

Here’s my theory:

Student Unions run elections that use AV (for single candidates and STV (for blocks). NUS uses both too. So do Trade Unions. National elections in political parties often use both systems too. Some even add exotic twists called ‘constraints’ that ensure there’s a gender balance.

Politically active people have probably voted in loads of AV and STV elections in these forums without really knowing which was which. They all look the same: you rank the candidates in order of preference and then a magic answer comes out at the end.

Only a small number of them – of us – really understood what was going on behind the curtain: the election geeks, a political subculture. We were always being called on to run models and work out surpluses and transfers; we sit in on counts and double-check the results (I once helped a friend take his rightful seat on a Trade Union executive after a miscount); in small elections, we work out that we can lend another party or faction twelve 1st-prefs in return for their transfers and get both of us elected – but not fifteen because we’d both lose.

As one of these select few, I’ve always been surprised how difficult a lot of highly intelligent political people find AV and STV.

This, I think, is why the debate is quite shallow. It’s not dumbing down, but a genuinely poor understanding of the issues by many of the key advocates. When No supporters use anti-PR arguments against AV or say it will let extremists in, some of them are just confusing it with STV. When Yes campaigners say AV will get rid of safe seats or will ensure that MPs get 50% of the vote, it shows that they don’t really understand how AV will work.

I also think that among the political classes, these different experiences of AV (and STV) are probably at the back of people’s minds and shaping how they respond to the whole question.

We’re hurtling towards a referendum at full speed, and we’re about to crash into it. Despite not having a preference yet, the least I can do for now is to talk a bit about it.

So this is the first in a series of posts on the AV referendum. The next titles are below. Maybe by the end I’ll have decided how to vote.


  • Misunderstanding AV
  • Does my vote count?
  • Running more than one candidate.
  • De do ron ron ron
  • Why it isn’t very important

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