The recent Tasmanian election was very interesting and complex to follow, right down to the final preference distributions, but it also did a good job of translating votes into seats.
The House of Assembly was expanded in size from 25 to 35, and with that became a system more likely to produce a highly proportional result.
Now that the results have been finalised, it’s clear that this was a very proportional translation of votes into seats.
If we just start by looking at the 2024 results by party, they line up quite neatly.
The translation of votes into seats was almost perfect for Labor, the Greens and the independents. A proportional seat share for the Liberal Party would have been one seat less than the actual result, which is a pretty small winners bonus.
The Jacqui Lambie Network was slightly over-represented, but a majority of that deviation would have gone away if they had stood in Clark. Based on a comparison of how the JLN polled in the 2022 Senate election and the 2024 state election, I would expect they would have polled 4-5% in Clark and not won a seat, but that would have brought their total vote close to their seat share.
There were a few small parties that polled around 2% and didn’t win seats, but that is typical in most proportional systems.
So this information made me wonder: how did this result compare to past elections? There’s a reason to think that an increase in the district magnitude and an increase in the total number of seats would both lead to a closer translation of votes into seats.
The standard metric for measuring disproportionality is the Gallagher index. It compares the vote share to seat share for each party. If there is no disproportionality, the score is zero.
Tasmanian elections generally have much lower Gallagher scores than you get for more majoritarian elections for the federal parliament or the big mainland states. The worst score in the last four decades was almost 10 in 1998, but that is in the typical range of disproportionality for the House of Representatives, and much less than the score of 16.5 for the 2022 federal election.
A system with less proportional features can still fluke a very proportional result on occasion, but it won’t be able to do it consistently.
It does look like there was an uptick in disproportionality in 1998, when the Assembly was cut from 35 to 25. The 2002 and 2010 elections were fairly proportional, but the 2014, 2018 and 2021 elections were all amongst the least proportional.
We will need to wait and see if the 35-seat system will continue to produce such proportional outcomes, but I suspect it won’t bounce back to the disproportionality we saw last decade.
There are often arguments around whether Single Transferable Vote counts as a proportional system, but there’s no doubt in looking at these results, either statewide or in a single electorate, that it can be proportional. If there is limitations in its proportionality, it is because it is usually used in very low magnitudes. All PR systems will be less proportional when magnitudes are low. And the small size of Tasmania’s parliament means that random variations from the statewide trend are less likely to be cancelled out.
At some point in the near future I’ll be trying out some calculations to see how Tasmania’s votes might have been translated into seats under some other electoral systems.
Very thorough assessment. Thank you.
Hi Ben, I’d be interested to see your estimate of what the results may have been with 5-member districts (either seven or nine districts).
Kevin Bonham has done so.
It was 10 LIB, 8 ALP, 3 GRN, 2 JLN, O’Byrne and Johnston.
So the dynamics would’ve been exactly the same. LIB+JLN would’ve fallen one seat short of a majority, while ALP+GRN could get to a majority with either JLN or the independents.
Is there a correlation between how low the Gallagher index is and how well the Greens do? As the third largest party in Tas, I would assume that for the ’98 – ’21 period that they were the most likely party to underperform on a state level.
Ben: thank for this. I noticed that this was an early election about “stability of government”? So I presume terms aren’t fixed in Tasmania? And I presume Tasmanians don’t share their putative premier’s desire for “stability”? Should be an entertaining couple of years.
Meanwhile with 52 full time Federal & State politicians for an enrolment of about half a million voters the furniture must get polished almost every day in Tasmania?
I’d be curious to look into how district magnitude corresponds to proportionality. (Of course it’s complicated because there’s a myriad of factors that can affect this.) Going from one to three leads to a huge increase in proportionality, and the gains taper off beyond that. Perhaps five or seven may be the sweet spot?
Nicholas, there’s a paper called “the electoral sweet spot” which I did a podcast about with one of the others, Simon Hix. If you find the post for the podcast you can also find the paper. That includes a chart showing how magnitude relates to proportionality.
More generally, I suggest that the work of Matthew Shugart and Rein Taagepera is relevant here. Their book Votes From Seats but they also have shorter work. They look at how two metrics – magnitude and the size of the assembly – and how they relate to the number of parties who win seats but also proportionality. I suggest that magnitude-3 districts would be a lot more proportional at a national level if you’re electing 150 members than if you’re only electing 15 on a local council.
I also did a podcast with Shugart about his work.
I think the Gallagher Index is a great technology but it’s not equipped to measure STV. I have the radical belief that STV has better principles of proportionality, fairness, and equality than the Gallagher Index itself. Gallagher Index reads some *good* phenomena in STV as *bad*.
Think about a multi-member district with magnitude 7.
Party A 49% of the vote
Party B 47% of the vote
Party C 4% of the vote. Party C voters strongly prefer Party B over Party A.
In any most non-STV PR systems the results will be:
Party A wins 4 seats
Party B wins 3 seats
Gallagher Index = 7.05
In an STV system the results are most likely to be:
Party A wins 3 seats
Party B wins 4 seats
Gallagher Index = 8.85
In this case the Gallagher Index is seeing STV treat votes more equally and fairly by allowing otherwise unrepresented voters to have some say on the outcome but interprets it naively as Party B being “over-represented.”
The same thing can happen with surplus values as well, Gallagher Index can see cohorts of voters for similar parties aid each-other with their surplus vote value and naively think parties are “over-represented.”
Actually it is 67 full time counting the Upper house.
The other thing possible is
To create a say 5% threshold to gain any seats as quota was 12.5% suspect this would not have changed the tas election result
Isn’t this though an argument against proportional representation? What we have been left with is an unworkable mess, with little chance of a stable government and most likely a new election in the next 6 months. There is little enough change of Libs and JLN forming a stable government, yet I have seen people seriously argue that Labor + Greens + O’Byrne + Johnson + Garland could form a stable government?????
We’ll see how things go. But that is a reflection of how people vote, and alienation from the major parties. It might take some time for the parties and voters to get used to a more complex party system. Perhaps JLN will mature, or they will blow up and disappear. But I don’t think you can have a situation where the major parties poll just 65% of the vote but you sweep that under the covers and elect a majority government anyway. JLN will be held accountable and if they don’t do well they will lose support and lose seats.
Labor Voter, I believe these systems work best when there is already an environment where parties are expected to come together and co-operate on various matters, not just adapt a ‘go it alone’ attitude. This is the case with countries like Scotland and Germany which regularly form coalition agreements between two or more parties to form government. Whilst there are disagreements, they are resolved quickly.
Even other western democracies like Canada and regularly manage stable minority governments with either official or unofficial coalition agreements made between two or more parties.
Also, if JLN appears to be a weak force and their vote collapses – voters can always switch back to the major parties again. This happened with the UK in 2015, the Liberal Democrats suffered a huge collapse in their vote and most of it went back to the Conservatives who managed to secure a majority after governing in coalition with the Lib Dems.
Actually Yoh An, for every Germany there is an Italy, an ungovernable mess where every coalition is dependent on a random small party that essentially holds the main parties to ransom and brings them down when they don’t get their way. Also, didn’t Germany have the SDP and CDU govern in coalition for a while, as the SDP couldn’t cobble enough seats to get over the line and the CDU didn’t want to govern with the help of AfD?
I just worry this is where academic theory meets the road of reality and it isn’t anything like what the theorists assume.
Italy does not have a proportional electoral system. They use a system where a part of their parliament is elected proportionally but that is overwhelmed by the FPTP majoritarian element. It doesn’t tell you anything about how PR works.
I suggest you listen to my podcast about the Electoral Sweet Spot. There are better and worse PR systems but when it’s designed well you address all these concerns and have highly stable yet representative systems.
Agree Ben, I think NZ using MMP whilst not an ideal system works well in practice with almost all of its minority governments being able to go full term without too many disputes between parties.
Also, Labor Voter – whilst you do bring up Italy (and I can also include Israel and possibly Greece) as examples where coalitions have broken down, it appears to be more to do with the parties themselves whose ideology hinders their ability to compromise on various matters.
Ben, isn’t the Italian system 2/3rds PR 1/3rd FTTP? That seems like the PR would overwhelm the FTTP, but maybe not how it works in practice.
Yoh An, yes I agree (I was going to suggest Israel but in the current circumstances thought it was prudent to ignore it) to an extent – but I do think any system that works against majoritarian rule will exacerbate any party wiling to play hardball.
Thing is, I think a pure proportional result like this is good from an upper house POV – where they can’t enact legislation but do get to review/amend/block legislation, fully review legislation and the executive through the committee process etc. But when it comes to forming Government, it is far too tempting for the smaller parties to get their pound of flesh in order to allow a government to form and cause chaos in the house, and that is why I am more in favour of a majoritarian type set up for the lower house.
I don’t proportional representation would ever be introduced in Australia probably due to constitutions which both LNP and Labor will almost certainly oppose because it almost guarantees to prevent a majority government plus even voters would most likely reject it as Australians are more opposed to Minority Government and Third Parties compared to Europe
Yes, Italy is 2/3s PR, but the other third skews very heavily, which is enough to produce a majoritarian result. It also has the effect of concentrating most parties into two big blocs that run together for the FPTP section.
At the last election the right-wing coalition won 120 out of 146 FPTP seats. Easily enough to make the PR tier irrelevant.
If it was MMP it’d be different, but it’s not.
I don’t mind if democracy is messy under a proportionally elected chamber of parliament. The whole idea of democracy to me is that the different views held by people will be represented in governance, and if that requires compromise and negotiation, that’s not a bad thing. I much prefer that compared to giving a free hand to any one party in order to bring “stability”. There are plenty of places around the world with stable governments, but ones that don’t reflect the opinions of the people. North Korea and Eritrea come to mind.
@MLV – I think low-magnitude PR mostly ensures a system is more governable by simplifying the race and in the end Tasmania now has 4 parties. It’s not that many really. I think you’re blaming PR for a lot of issues that are actually about both major parties being really unpopular and the election being close. If this had a 2PP it would probably be about 50/50. So if this was a single-member system you might have ended up with a hung parliament anyway.
@Marh yes people often have a preference for what they know, but I don’t know that you can say that Australians are more opposed to minority government.
And if people keep voting for minor parties and independents they’re gonna get minority government even under the single-member system. It just does a poor job of accurately representing people in producing that result.
I think it is fine for legislation to be messy Wilson, particularly when you have multiple pathways to pass legislation, but not for Governance, where you want a certain amount of stability. The other thing is if you have coalition governments (true coalitions not the quasi single party we have on the right) you tend to find a lot more backroom deals to get legislation into parliament then relatively little debate, rather than introducing legislation then negotiating to get it through which leads to lots of parliamentary and public debate. Much as I am not a fan of the Greens, what they are doing in this parliament is far more agreeable to democracy than forcing Gillard to to a U-turn on an election policy (yes I know technically it wasn’t a backflip but that is how people saw it).
@Ben, I agree it would have been close result under a 2PP system, but had the previous election been held under a 2PP system, the Libs wouldn’t have been held hostage by 2 disaffected members so there wouldn’t have been an election.
I do think a lot of people confuse Executive Government with the legislature, and think what is good for one is good for both. I happen to disagree, and in fact I think we have it pretty much right federally (although I would have OPV and a more proportional Senate – all 12 elected every 3 years).
I think if the Labor PV keeps dropping, AND its 2PP remains stable enough for it to form minority governments fairly often AND the coalition is able to recover somewhat from the Teal incursion, Labor might start to think that PV isn’t such a bad idea. Eg. If we’re in a situation where Labor consistently can’t get a Majority but the L/NP can, A PV system could potentially re-level that playing field for them.
Mostly Labor Voter, every deal requires two parties to agree. In hindsight it wasn’t a useful deal for either party in the long run, but it’s not the responsibility of the Greens, or any other party, to help the governing party fulfil any promises it made. Their only responsibility is to the vision they campaigned on for making Australia better.