Monday, 2 May 2011

Should the UK adopt the Australian Voting System?

The UK referendum on a new voting system has generated heated debate. But it’s not as if the idea hasn’t been tried before. Australian has used a preferential system since 1918, and it has generally worked out pretty well.

On 5 May, UK voters will be faced with the referendum question:
'At present, the UK uses the 'first past the post' system to elect MPs to the House of Commons. Should the 'alternative vote' system be used instead?
Naturally a simple question like this masks many complex issues so let’s cut to the chase. The core issue is whether you can vote for someone who’s not likely to win without throwing away your vote. Without that assurance, it’s almost impossible for new parties to arise outside of truly exceptional circumstances. Take the last UK election, where polls leading up to the election were showing an unprecedented vote for the Liberal Democrats. As election day loomed, voters defected two the two major parties. Why? Because they feared that voting for a candidate who had a faint chance of winning would result in someone they really did not want taking out their constituency.

Since the UK is currently facing this issue, I’ll use the UK term for electoral district: constituency. In Australia, we call the same thing an electorate.

I’ve lived in Australia for the best part of 9 years and run as a candidate in two elections, as well as managing two other candidates’ campaigns. I’ve also lived in South Africa and the US, which gives me a bit of international perspective. In Australia, we have a bewildering array of variants on “alternative voting” systems. Here are a few:
  • compulsory preferential (used in federal lower house elections) – you must number every candidate for your vote to count
  • optional preferential (used in some state elections, like Queensland) – you may number 1 or more candidates (if only one, any mark will do)
  • above the line voting (used in the federal senate election) – instead of numbering individual candidates, you select one party ticket, and rely on the party to have negotiated a sensible flow of preferences
  • single winner (the most common model in lower house elections including the federal lower house) – after distributing preferences, you elect exactly one person
  • multi-member constituency (used in smaller states and territories) – each constituency elects several members
We can easily get lost in the details of these variations and indeed that is one of the hazards of a complex counting system: party machines can manipulate the poor understanding the less politically engaged have of how the system works. However, that hazard is relatively minor compared with blocking the rise of a new, fresh political movement because voters go for one of the bigger parties for fear of “wasting” their vote.

Let’s consider an example where four completely fictitious parties, Reds, Blues, Greens and Yellows, are contesting a seat. Polling shows that either the Reds or Blues will win in a first past the post system, with the Greens an outside chance, and the Yellows very little chance. 90% of supporters of the Greens vote Yellows, absent a Greens candidate, and vice-versa. The Reds and Blues supporters dislike each other’s policies so much, they would split their votes between Greens and Yellows if their own candidates dropped out. If everyone voted according to their first preference, the vote would be (in this fictitious example):
  • Reds – 28%
  • Blues – 27%
  • Greens – 25%
  • Yellows – 20%
In a first past the post system, as you have today in the UK and in the US House of Representatives, the Reds would win with less than a third of the vote. The Blues supporters would be very unhappy, as would a large fraction of Greens and Yellows supporters. In a real election, with this sort of expectation, potential Greens and Yellows voters would split their support over Reds and Blues, hoping their least worst choice would win, making it that much harder for their actual preferred party to win.

Now, let’s consider a vote on the basis of an Australian-style transferable preferential voting system. To keep it simple, we will assume compulsory preferential, so every ballot has to have every candidate numbered. With the above results, the Yellows would drop out after the first count because their vote is the lowest. 90% of the Yellows vote goes to the Greens, and the rest is split evenly between the other two parties:

  • Reds – 28%+1%=29%
  • Blues – 27%+1%=28%
  • Greens – 25%+18%=43%
  • Yellows – 20%-20% = 0 (dropped out)
At this point no one has passed 50%, so the lowest drops out, this time the Blues. Any second preferences of Blues voters to Yellows are ignored since they are out of the race, and in that case, the third preference gets counted instead. Thus all the Blues votes flow to the Greens (remember they hate the Reds’ policies and put them last), so the counts now become:

  • Reds – 29%
  • Blues – 28%-28%=0 (dropped out)
  • Greens – 43%+28%=71%
To keep things simple, I didn't take into account that Yellows voters who put Blues ahead of Reds could have either put Reds of Greens next. Not only is this a very different outcome to the first past the post election, but voters are much more comfortable with giving the smaller parties a look because they know their first choice vote is not wasted if that party is too small to win. While the Greens were not the party with the biggest support on the first count (the “primary vote” in Australian terminology), they were the party that was disliked the least. Had the Reds candidate won, not only the Blues supporters but also a substantial fraction of the Yellows and Greens supporters would have been unhappy.

The major downside of the system in practice is that parties can manipulate public perceptions about the system to sow confusion. In Australia, except in a few jurisdictions where the practice is banned, parties hand out “how to vote” instructions outside polling booths. These instructions are no more than a suggestion, but many voters in my experience think that you have to follow the instructions once you’ve chosen which party to support. Consequently, there is a lot of horse-trading before elections between parties on how to order each other on their how to votes, in exchange for favours. This is however an easy problem to solve: better regulation of the  type of information that may be handed out on polling day can eliminate confusion, as can a more pro-active advertising program by the election agency.

Australia very seldom has hung parliaments; we are in an unusual situation currently with both the federal lower house and the Tasmanian state parliament with minority governments. This has happened because the major parties are uninspiring, rather than because of the electoral system. We have on the other hand a vigorous history of voting in independents and small parties, who have, in the words of the late great founder leader of the Australian Democrats Don Chipp, kept the bastards honest. Well, to a degree. There’s just so much you can do with the raw material.

As UK voters ponder which way to vote on the referendum, remember this. You can get exactly the same outcome as in the current system if you don’t like any of the smaller parties or independents running. Just number Labour and Tories ahead of them, and, if this is the general sentiment, they won’t stand a chance of winning. On the other hand, if you are really fed up with the major parties, you open up a new alternative of giving someone else a chance – without wasting your vote if they don’t make it.

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