STV is not PR
Saturday May 8, 2010
The NYTimes, reporting on calls for electoral reform in the UK:
The Liberal Democrats, supported by the Electoral Reform Society, favor a type of proportional representation based on the so-called single transferable vote. Under that system, voters rank the candidates in order of preference. Votes for the lowest-ranking candidates are redistributed to the voter’s second choice. The system is devised so that if a party wins, say, 25 percent of the vote, it should win 25 percent of the seats.
As any observer of Australian politics would tell you, that is not how Federal House of Representatives elections work. For example, the Greens won 7.8% of the House vote in 2007, but no seats. The Nats won 5.5% of the vote, but 10 of 150 seats (6.7%).
In 1990, the Australian Democrats won 11.3% of the vote, but zero seats.
The geographical distribution of party support still matters if you have a district-based system. STV doesn’t get you PR, at least not “automatically”, and its a misnomer to call STV a form of PR.



I’ve heard it called a semi-proportional system, which I think is a good description. Hare devised the system not as a way of getting proportional representation but as a method of minimising wasted votes.
I’m glad someone points this out – this has been irritating me ever since I live in Ireland, where everybody talks of the (STV) system they have here as being a PR system … Coming from the Netherlands, which probably has the most proportional system in the world, that’s very strange to read indeed … (Especially when people started talking about a PR system to elect the chair of a local club (!) …)
Is there no distinction between AV with single member districts and STV? My understanding is that the Lib Dems support STV in multimember districts.
Hey Simon and Antony,
I’m with Peter. I believe the Lib Dems support STV in districts that elect 4-5 or so members. Reduce the number of districts from 650 to around 130. Although I still like Antony’s description of semi-proportional.
If STV = “preferential voting in the context of multi-member districts” (e.g., Hare-Clark type setups), then ok, yes, we get down a little down the road towards PR.
But if we have AV or “instant-runoff” (as the Americans tend to call it) in single-member districts, then I’d stand by my earlier comment.
I wonder what Clegg will hold out for, what the major parties might be willing to offer…
[...] is high-threshold PR Contra Simon Jackman, the single transferable vote is a form of proportional representation, albeit one with a very high [...]
I guess what they fear is the BNP getting any seats, so there will never be anything close to proportional.
Yes, the textbook classification seem to have AV as a subset of STV, that is, AV is STV in single member electorates.
But there has been lotsa confusion, granted, and several Oz journos seem to think we have PR in lower house.