I will be doing my usual liveblogs for Nepean and the Tasmanian Legislative Council on May 2, and for Stafford on May 16.

I will also be doing a livestream for the Farrer by-election on May 9. This will be my second livestream following the South Australian election livestream in March. I will have a number of guests and we will be livestreaming from 6:30pm. You can watch the livestream on YouTube at this link.

I will also be doing a live event shortly after the Farrer by-election. On Monday, May 11, I’ll be a guest for a live recording of the Democracy Sausage podcast at the Australian National University in Canberra. The event is free but you need to book a ticket. I hope I’ll see you there!

9:38 – Labor’s lead in Liverpool South has fallen back a bit, now leading 37-22, with almost 5000 postal votes counted. Every election day booth has reported but no pre-poll votes.

7:45 – With 44 booths reporting in Newcastle, Gavin Morris is on 49.1%, and I now project he will fall just short of a primary vote majority. The swing against Labor is now 14.7%.

Meanwhile in Liverpool South, my best estimate of a swing against the Liberal Party (based on mayoral booths) is 18.3%, with Labor’s vote up 16%. The Labor primary vote is just over 40%.

7:31 – Worth noting the Greens are outpolling Labor in Newcastle.

7:22 – Labor candidate Zeli Munjiza is leading in Liverpool South, with 39.31%. The Liberals are way behind on 22.5%. This is looking pretty good for Labor. That is with nine booths reporting.

7:19 – By my count, 25 of the election day booths have reported in Newcastle, out of 48 booths. Gavin Morris is on 50.6%, which is a swing of 18.5% compared to Ross Kerridge in 2024.

The Labor vote is down 14.3%, the Liberals are down 5.5%, and the Greens are up 1.5%.

7:03 – Meanwhile we have one booth in for Liverpool South and it is Hoxton Park Anglican. Labor has the lead, whereas the Liberal Party easily won the primary vote for mayor there in 2024. I don’t have council booth figures so I’m comparing to the mayoral results.

7:00 – Thirteen booths have reported in Newcastle, and Gavin Morris is just over 50% of the primary vote. A very good start for him.

6:17 – I will be comparing the new election results for Newcastle with those from 2024. I was hoping to do the same for Liverpool but I have discovered that the booth-level ward results are missing from my dataset. Presumably this was to do with the election being run by a private provider. I thought I had solved that problem but apparently not.

6:00 – Polls have just closed for three council by-elections in New South Wales. I wouldn’t normally cover council by-elections, but two of them are quite large.

In the City of Newcastle, there is a by-election for the Lord Mayor. Ross Kerridge resigned recently due to the tolls of his cancer treatment. I have written a guide for this by-election here. Ross Kerridge was elected at the head of an independent team called Our Newcastle in September 2024, defeating the Labor incumbent by a 1.7% margin.

Kerridge has endorsed independent Gavin Morris. His main opposition is Labor councillor Declan Clausen. The Greens and Liberal candidates are also sitting councillors. The twelve councillors split 5 Labor, 3 Greens, 2 Liberals and 2 independents elected on Kerridge’s ticket. If Labor gains the mayoralty, they will be just one vote short of a majority.

In the South Ward of Liverpool council, there is a by-election to replace Betty Green, who was won of four Labor councillors elected to the council in 2024. The council is split down the middle at the moment. In 2024, Liberal councillor Ned Mannoun returned to the directly-elected mayoralty, along with four other Liberals, four Labor and two independents. Betty Green was elected deputy mayor in September 2025 with the support of the Liberal councillors, putting her out of step with her own party. She resigned from council some time later.

Part of the interesting story here is that Liverpool chose not to use countbacks following the 2024 election. If countbacks were used, this seat would have been filled by countback shortly before the deadline for the last use of countbacks for this council term. Instead the by-election has apparently cost $900,000, and has been quite bitter between the major parties.

At the 2024 election, the Liberal Party polled 40.2% in the ward, and the ALP polled 30.2%. The right-wing Our Local Community also polled 9.4%. So it’s likely that a status quo result would see the Liberal Party gain a sixth seat of eleven, giving them a majority on the council.

There will also be a by-election for the A Ward of Uralla Council. I have no plans to cover this contest.

The recent South Australian election was off the charts for disproportionality, with a government winning an enormous majority with less than 40% of the vote. Two right wing parties split the vote between them fairly evenly, and won very few seats from that vote.

From today’s post, I am going to look at how that disproportionality compares historically, and look at what the result could have looked like under some kind of proportional representation (PR) system.

The most widely-accepted method of calculating disproportionality is the Gallagher index of least squares. This method compares each party’s share of the vote and share of the seats and adds up the differences. A score of 0 would indicate precise proportionality between seats and votes. Say, every party received exactly 100 votes per seat. I have previously analysed the Gallagher index for a number of Australian jurisdictions and you can find those posts here.

South Australian elections have been steadily increasing in disproportionality in recent decades with occasional spikes. The previous high of 20.65 took place in 1993. The Liberal Party polled just over 50% with Labor just over 30%, but won 37 seats to 10, with 9% of the vote going to the Democrats for no seats.

But the 2026 result is off the charts, with a score of 28.4. By comparison, the 2025 federal election produced a score of 23.1 if the Coalition is treated as separate parties, or 22.1 if the Coalition is treated as a single party.

To give a sense of what could be possible under a proportional system, I have split up the 47 existing electorates into three maps based on different magnitudes (the number of members per electorate) – three, five or seven. Unfortunately 47 is a prime number so it’s not possible to make every seat the same magnitude, but I made them as close as possible. I refer to those maps as M3, M5 and M7, while the actual electorate map is M1. I have then taken the actual 2026 results, and the 2022 results matched to the current boundaries, merged them into the multi-member electorates and estimated who would have likely won each seat.

Now I should note that this is just a simulation. A different electoral system would undoubtedly lead to changes in the party system and how people vote. But still, it is interesting to see how a given vote spread produces different results under different systems.

I would also ask you to not put too much importance on the specific electoral boundaries or the names. I have tried to draw them in a sensible way, but if real electorates were drawn they would be drawn afresh, not just merging existing electorates, and there would be opportunity for those with local input to feed in.

Having said all that, this map shows the three maps I drew. Adjacent seats in the same colour are merged into the same multi-member electorate. You can click on any seat to see the result for that merged electorate at the 2022 and 2026 elections.

I conducted a similar exercise using the results of the 2019 and 2022 federal elections.

One thing that jumped out was that fragmentation goes up as the average magnitude increases. Under an M3 model, the result is reasonably proportional, but does give a small winners bonus to larger parties, compared to a purely proportional result.

This chart shows the results of the three models in 2022 and 2026, compared to the actual result and a purely proportional result.

The scale of Labor’s victory beyond their vote share in 2026 really stands out. Their proportional share of seats would have been 18 seats, but they actually won 34 seats – almost double. The disproportion was much less in 2022, when they won eight more seats than their proportional share.

The M3 model in 2026 still leaves Labor with a slim parliamentary majority, but in every other proportional scenario the Labor government usually ends up slightly short of a majority. Yet there is always a progressive majority.

Meanwhile, on the right, One Nation would have won more seats than the Liberal Party under any 2026 model. Once there is even some basic proportionality, the higher One Nation vote means they win more seats. One Nation piled up a lot more votes than the Liberal Party in seats they didn’t win, but once there are 3-member electorates, there’s usually at least one right-wing seat in each electorate.

The performance of One Nation is particularly notable. You see a lot of anger at the electoral system from One Nation supporters, but pretty much none of it seems to be directed towards improving proportionality. Instead it is usually focused on preferences. A wide variety of parties would benefit from a more proportional system. At these recent elections, it would have benefited all parties other than Labor. The Liberal Party has a lot less room to fall if results are proportional, and the Greens and One Nation can win their fair share.

Sullivan was elected twice as a Labor MP in 2020 and 2024, but was expelled from the party in May 2025 over domestic violence allegations, and passed away last week.

The by-election will likely be held around the middle of 2026. Stafford is a relatively conventional Labor seat in the northern suburbs of Brisbane. I don’t think it’s a particularly good area for One Nation, but I’m sure they will make their presence known.

Read my guide to Stafford here.

The typical process of counting ballot papers at the election doesn’t usually distinguish different types of informal votes. A vote could be informal because the voter has left their ballot blank, because they’ve only numbered one box, or because they have made a mistake in their numbering. Federal informal voting rules are quite strict, and there could be numerous reasons why a vote could be informal.

If you want to know more about why voters are casting informal ballots is by conducting a survey where you revisit those ballot papers and categorise them, recording the cause of the informality.

The last survey of informal ballot papers took place in 2016, but the AEC had promised to produce another report after the 2025 election. You can read it here.

The AEC has not reviewed informal ballot papers in all seats, but instead has selected 25 seats to review. They’ve reviewed the ten seats with the highest informal rate, another eleven seats which had at least one booth with 50 or more votes and an informal rate of over 25%, and four more seats as a comparison. These seats have a bias towards New South Wales, since informal voting tended to be higher in that state.

Past informality reviews have split the different voting categories between those that are apparently deliberate and those that are apparently accidental. Blank ballots, for example, are presumed to be deliberate while those where a voter has numbered some boxes but hasn’t successfully filled out the ballot are presumed to be accidentally informal.

For this report, the AEC has categorised completely blank ballots, and sorted those with some numbers into those with a single ‘1’ only, those with numbers 1-6 (which is what would happen if you took Senate advice and applied it to the House) and those with other incorrect numbering. A small number of ballots involved a voter identifying themselves (0.2%) and 8.4% don’t fit into any of those categories.

A clear majority of informal votes involved someone filling in the numbers, specifically:

• First preference only – 16.9%
• Numbered 1-6 only – 12.3%
• Incorrect numbering/method – 37.0%

Unfortunately the data doesn’t make it entirely clear if all of these votes have a clear ‘1’, but the first two categories at least would count as formal under optional preferential voting (OPV), and I suspect most of the incorrect numbering would also count as formal.

The report breaks down the type of informal votes based on the number of candidates on the ballot.

As the ballot gets bigger, numbering issues become a more significant issue, with 1-6 numbering issues making up 12-19% of informal votes once the ballot is longer enough for 6 preferences to not produce a formal ballot. This is consistent with data we had on ballot paper size being correlated with informal voting.

The AEC survey identified a significantly higher rate of 1-only votes in New South Wales, the only state currently using an OPV system for single-member electorates in state elections.

The AEC survey also looked at specific polling places with extremely high informal rates. There was one booth, Missabotti in the NSW seat of Cowper, where 45% of votes were informal. The AEC has identified that 64% of those informal votes were voters who numbered 1-6. Eleven candidates ran in Cowper, so a voter filling out six preferences didn’t come close to a formal vote. It does look like incorrect ballot paper instructions (potentially combined with incorrect word-of-mouth) did have an effect there.

The big question for me is how much informal voting is driven by the requirement for voters to number every box. There will always be people who intentionally vote informal simply out of protest at being required to cast a vote, and those voters are easy to identify through blank ballots or scribbled messages. But then there are those who cast a vote with a clear intention, but aren’t counted because of our strict formality rules.

It’s a bit hard to compare like-with-like between 2016 and 2025, both because the categories have changed slightly and because the 2025 survey doesn’t cover every seat. In 2016, incomplete and non-sequential numbering made up 40% of informal votes, and blank votes made up 25%. I think it’s also possible that the “incorrect numbering/method” category in 2025 would cover ticks and crosses, which brings the equivalent number in 2016 up to 48%. But in 2025, that number is up to about 66%. So it does seem like numbering issues are playing a bigger role than they used to be.

The AEC report seems to have an unspoken assumption that anyone who just numbers one box, or numbers a handful and then stops, has intended to vote formally and has misunderstood the rules. But I think it’s entirely possible there are voters who refuse to mark certain preferences, and know that their vote will be informal. On the right, One Nation has been sending signals of such a position, and I think we could see some voters on the left who refuse to preference either major party. Right now it is the position of the electoral system that it’s too bad, those voters have to number every box. I’m not so sure.

In this post, I’m going to look at what a new South Australian pendulum could look like, look also at seats where there was a chance that another party would have made it to the top two, and what margin that could have produced, and use some triangular graphs to show how the contest played out in particular types of races.

For a while now, my pendulums have not strictly obeyed the rules of the traditional two-party-preferred pendulum. I include all seats held by the government on the left sorted by the two-candidate-preferred margin, even when that is not the 2PP margin. It does mean that sometimes you need to be aware that not all seats are alike – you wouldn’t necessarily assume swings in Labor-Greens contests would be similar to Labor-Liberal seats. Effectively the pendulum becomes more about listing seats broadly in line with marginality rather than using it as a predictive tool.

It turns out this method doesn’t actually work too badly in the case of the 2026 South Australian election.

Most seats in South Australia ended up as contests between Labor and one of two right-wing parties: either One Nation or the Liberal Party: 38 out of 47 seats, to be exact.

So I’ve slightly modified my traditional pendulum to list Liberal and One Nation seats mixed together on the right, with independent seats at the bottom right.

This pendulum allows you to get a sense of how much of a swing would be needed from Labor towards these two different right-wing parties to deprive Labor of a majority.

If Labor was to lose eleven seats, it would deprive them of a majority. If One Nation and the Liberal Party gained fifteen seats between them, they would hold a majority. I don’t know what such a majority would look like, but it’s a notable threshold.

This pendulum shows that a uniform swing of 8.5% would leave Labor without a majority, and 10.3% would produce a Liberal-One Nation majority. If we assume that the balance between Liberal and One Nation was to remain steady, One Nation would pick up more of those seats than the Liberal Party and would be the bigger party in such a majority.

While a pendulum can still be interesting, it presumes that there are only two candidates of interest in a seat, and that the two-candidate-preferred pairing is the only possible such pairing. Of course, this is not true.

There has been a number of seats in the past where there was a tight margin on the three-candidate-preferred between two candidates, and the outcome of that contest would then have an impact on the final two-candidate-preferred margin. Sometimes one contender produces a much closer margin than the other contender, and sometimes it actually changes who would win.

In some cases we have hard data on the margin in the alternative scenario, but it’s also possible to take preference flows from other seats and use them to make an estimate.

As of this election, there are now enough of these seats that it’s worth dealing with these systemically, and producing a table of these alternatives.

The gap between second place and third place on the 3CP was 12.1% on average. There were 24 out of 47 seats where the margin was less than 10%, so I’ve focused on those seats. In two cases (Heysen and Croydon) the margin was less than 1%. This really matters in Heysen, and doesn’t matter at all in Croydon, as we’ll see.

The alternative 2CP margin only changes the outcome in two seats. In Hammond, Labor topped the 3CP count, but lose to whoever out of Liberal or One Nation makes the top two. One Nation outpolled Liberal by 4.9% on the 3CP. The 2CP margin over Labor is about the same for either party. In Ngadjuri, One Nation beat Labor. If the Liberal Party closed an 8.5% 3CP margin over Labor, they would have then won on Labor preferences.

In some seats, the alternative margins are fairly similar, but in some cases they produce very different margins.

There’s a bunch of seats where the Liberal Party is substituted for One Nation, or vice versa, and the margin ends up quite similar. There are ten seats that flipped between ALP-ON and ALP-LIB, and they won nine (the remaining seat was Hammond). The Liberal Party would have come closer to winning in Enfield and Torrens, while One Nation’s margin was wider in every seat. But none of them are particularly close.

There are four seats where independents have a big impact on the margin. Independents came third in Black, Port Adelaide and Flinders, with One Nation coming second on the 3CP in all three seats. My estimated margin gets much tighter if One Nation is replaced with the independent. It’s worth noting that there isn’t much of a sample size of One Nation preferences splitting between an independent and either Labor or Liberal, and it would undoubtedly vary depending on the specific independent. In this case, I’ve used the Kavel preference count to estimate One Nation preference flows between Labor and Independent, and I’ve used Finniss to estimate ON flows between Liberal and Independent.

In Narungga, the replacement of the Liberal Party with an independent actually significantly increases the One Nation margin from 0.2% to 12.4%. Independent preferences favour Liberal over One Nation, but Liberal preferences favour One Nation over the independent.

And then there’s Heysen, which doesn’t change much, but is the most marginal seat on this list on every measure. Liberal beat Labor by 0.6%. Labor beat the Greens on the 3CP count by just 0.4%. By my estimate of Labor preferences between Liberal and Greens (using examples from Heysen in 2014, federal elections in 2022 and 2025, and Prahran in Victorian elections), the margin is just 0.2%.

The other method for combining two-candidate-preferred and three-candidate-preferred information is through the use of triangular graphs. I have started producing graphs for recent elections showing all seats with a given combination of parties in the 3CP, showing who wins for a given 3CP. My first version of my federal graphs are in this blog post.

These have been inspired by Ben Messenger who first developed triangular 3CP graphs. He has published his own version of these graphs for South Australia here on Bluesky.

Unfortunately South Australia’s election was so fragmented that we can’t show every seat in one chart. I’ve made charts for three 3CP combinations that cover 39 out of 46 seats.

First up, this chart shows Labor-Liberal-One Nation contests – there were 20 in South Australia.

The lighter colours in the background show who would have won for a given 3CP, based on average preference flows (the same numbers used to estimate alternative 2CPs). The brighter dots are actual seat results.

Labor won most of these seats, but Labor needs a relatively higher 3CP to win in such a contest. Labor preferences slightly favour Liberal over One Nation, which explains the blue bulge sticking into the One Nation territory.

There were thirteen Labor-One Nation-Greens contests.

Labor won every single one of these seats, and generally can win with a lower 3CP than when they face two right-wing opponents.

There were six Labor-Liberal-Greens seats. It’s notable that the Labor zone is larger against the Greens than when One Nation is the third party, but One Nation also has a slightly larger zone than the Liberals. I think this reflects that Labor-Greens preference flows are less tight when facing off against One Nation – there are some Labor voters who preference One Nation when they wouldn’t preference Liberal, but that is also true of some Greens voters.

There is one seat that stands out above all others – the blue dot on the corner of the blue, red and green zones is Heysen. This chart makes it very clear that it’s a seat that all three parties could win with a slight nudge in their direction.

None of these methods are a perfect way of showing marginality of seats, but I think they are useful in exploring different angles of the contest. If we have more multi-party elections coming soon, I expect we’ll use these tools more often.

UPDATE: I’ve now added the Narungga data to this blog post. The rest of this blog post reflects all 47 seats.

Pretty much all of the analysis I am doing for this blog post is based on the three-candidate-preferred count, which is the second-last round of the preference count.

This South Australian election was extremely complex, with doubt about who would come in the top two, and with preferences potentially playing a larger role than in the past. So for this post I will be going through what the final preference distributions tell us about the shape of South Australia’s election: how preferences flowed, how close the gap was between second- and third-placed candidates, and how many seats featured a particular combination of candidates.

For my next blog post, I am going to use this data to publish not just the actual margins, but also my estimates of alternative margins, where it was plausible that a different candidate could have made the top two.

Let’s start by looking at how often a particular party made the three-candidate-preferred count.

Until 2026, Labor and Liberal made the top three in almost every seat. Over the previous six elections, Labor missed the top three twice, and the Liberal Party never missed the top three.

This year, Labor missed out in four seats, and the Liberal Party missed out in sixteen! One Nation reached the top three in forty seats. The Greens also had a significant downturn in the number of seats where they made the 3CP.

From 2002-2022 (and likely for much longer) there was always a third spot in the 3CP and that position has varied. The Australian Democrats had that role in most seats in 2002, and SA Best dominated in 2018. Otherwise, the Greens have usually made the count in a majority of seats, while Family First regularly made the 3CP in 2006-2014.

The specific combination of 3CP sets is:

• ALP-LIB-ON – 20
• ALP-ON-GRN – 13
• ALP-LIB-GRN – 6
• LIB-ON-IND – 4
• ALP-ON-IND – 3
• ALP-LIB-IND – 1

And the specific combination of 2CP sets is:

• ALP-ON – 25
• ALP-LIB – 13
• LIB-ON – 4
• ON-IND – 2
• ALP-GRN – 1
• ALP-IND – 1
• LIB-IND – 1

The next question I was wondering about was whether the gap between second and third has been shrinking. We have noticed this trend in federal politics, where we have more seats where the 3CP count becomes critical. It turns out that the gap has shrunk slightly, but is roughly back to where it was in 2018 when SA Best made a splash.

This actually rings true when considering the actual results. While there was a lot of seats where the top two wasn’t known before election day, there were only a few where it was unclear after election day, and most of those became clear without needing a full 3CP count.

Four seats had a gap of less than 4% between second and third on the 3CP:

• Heysen – ALP 0.4% over GRN
• Croydon – GRN 0.6% over ON
• Schubert – ALP 2.2% over ON
• Enfield – ON 2.9% over LIB

Only in Heysen did this come close to mattering for the result, but I’ll come back to that in the next post.

So did preferences make much of a difference to the result?

There were only two seats where the winner came from behind. In the other 45 seats, the primary vote leader ended up winning. In Finniss, independent Lou Nicholson came from fourth place to win, overtaking the Liberal primary vote leader. In Kavel, independent Matt Schultz overtook Labor.

In the seat of Hammond, One Nation topped the primary vote but actually fell behind on the three-candidate-preferred vote, into second place, and relied on preferences from the Liberal candidate to defeat Labor.

So overall it doesn’t look like preferences had a big impact one way or another, but there were a lot of them. Now that we have 3CP data, we can calculate how preferences flowed on the final round of the count. This is not the same as having preference data based on the candidate’s primary vote (apparently we will get this at the end of the year) but it does have the benefit of isolating other effects.

When comparing primary vote figures to the final preference count, it is difficult to isolate preferences from particular partisan elements – for example, how Liberal preferences flow. But by taking the second-last round of the count, there’s just the votes of one party left to be distributed. This does include votes that were cast for another candidate, but that’s not a bad thing.

So this next chart shows the proportion of preferences that flowed from each party for each two-candidate-preferred pairing. I’ve noted how many seats had this preference flow.

The most common 2CP contest was Labor vs One Nation. About half had the Greens in third, and most of the rest had the Liberals in third. Greens preferences flowed to Labor at about 80%, while Liberal preferences flowed at two thirds to One Nation.

In the Labor-Liberal contests, there is a similar mirror image, but even more polarised – Greens preferences were even stronger to Labor, while One Nation preferences favoured Liberal even more. But again, the parties of the left have tighter preference flows amongst each other than the parties of the right.

When you break down this data by electorate, there are some interesting trends. Greens preferences tend to be a little more pro-Labor in a race against the Liberal Party. In the seat of Elizabeth, almost a third of Greens preferences flowed to One Nation. That was a seat where a donkey vote would go to the Greens then One Nation, and it is a relatively weak area for the Greens.

Liberal preferences favoured One Nation over Labor in every seat, ranging from 53% in Enfield to 73.5% in Hammond. In general, One Nation does not favour Liberal quite so strongly.

Preferences do clearly have a skew, but it seems that multi-party politics means that they often cancel each other out. So I thought I would look at how much preferences helped each party, subtracting the party’s primary vote from their 2CP vote in every seat where they made the 2CP.

The political parties all benefited to similar degrees, but unsurprisingly One Nation does worst out of preferences, with Liberal doing a bit worse than Labor. The Greens didn’t do that well, but this only covers one seat (Croydon) which isn’t exactly Greens heartland.

It is remarkable, however, how well independents who made the final preference count benefited.

This can be seen clearly in my final chart, which shows the preference gain for each candidate in the top two, compared to that candidate’s primary vote.

Labor candidates fairly consistently did better than One Nation and Liberal candidates, but three independent candidates are way off the chart. Independents in Finniss, Kavel and Mount Gambier gained 30-40 percentage points from preferences. No major party candidate gains more than 28%.

That’s it for this post – in the next one, let’s look at some ways to understand the marginality of seats as we lose the simplicity of the pendulum.

This is the nineteenth book in a series that stretches back to 1958, and has covered every election since 1987. It’s been really great to be able to connect to that long legacy and I have been collecting older editions from the series.

I’ve done a quick video going through my collection which you can watch here.

The last six volumes (dating back to Julia 2010) have been published by ANU Press and all of them are available in full online, either as individual PDF chapters or the whole book as HTML, PDF or in ebook formats, and they are all available for purchase as hard copy editions. I think people who read this website will find many parts of these books of interest. Here are the links to the last six volumes:

• Julia 2010: The caretaker election
• Abbott’s Gambit
• Double Disillusion
• Morrison’s Miracle
• Watershed
• Landslide

I have been reading some very old psephological work from the 1970s recently, and a tool used often by analysts like Malcolm Mackerras was a histogram, often showing the distribution of swings. This is a special kind of bar graph where each column lists how many cases fit in that range or bucket.

For this post I am using primary vote totals as of Saturday afternoon, and two-candidate-preferred figures as of Monday morning. Neither is final, but they are close enough to give us a sense of the shape.

Let’s start with the primary vote.

This chart shows the distribution of primary votes for the three largest parties. Seats are coloured based on who won that seat.

The Labor part of the graph is stark – there is not a single seat where Labor polled between 29% and 35% of the primary vote. And every seat over 35% they have won. The only seat below that line where they have come close is Heysen, where a high Greens vote means Labor could win on a lower vote. We will get to the 2CP margins later, but Labor is currently on 49.5% in Heysen and their next best seats are Hammond on 45.2% and Ngaduri and Bragg in the low 40s. There just wasn’t many close losses for Labor.

So part of the story for Labor in terms of their vote efficiency is that when they lost, they lost big. But they also didn’t rack up huge piles of votes where they weren’t needed. Labor’s primary vote only exceeded 50% in six seats.

If you look just at the 34 seats Labor has won, their primary vote averaged at 45.2% and their 2CP vote averaged at 62.2%. They managed a primary vote that generally was enough to win modestly, and also did quite well on preference flows to push a vote in the 40s into the 60s.

Normally you would expect a party winning comfortably to also poll respectably in their losing seats, thus adding to their overall vote total. But Labor is now at a point where they poll very poorly in places where they aren’t winning. And this has a geographic component – most of those Labor wins were in Adelaide, and just one non-Labor win was in Adelaide.

The Liberal and One Nation charts are also somewhat interesting, in particular showing how many seats had very low Liberal primary votes. I think this is something we will have to factor in when we consider how much Liberal preferences flowed to One Nation – in some seats the Liberal vote collapsed so far that they don’t make up a dominant part of the pool of preferences.

This next chart shows the range of primary vote swings for Labor, Liberal and the Greens – there’s not much to show for One Nation, since they only ran in a handful of seats in 2022.

The Greens swings are very tight, with a majority showing a small swing. This isn’t surprising since the Greens vote tends to be a bit lower so doesn’t have as much room to move.

The swings were far from uniform for Labor – they gained a 24.6% swing in Waite and lost almost 20% in Light.

The Liberal swings were huge but there is clearly a focus point – 22 seats had the Liberal candidate suffer a swing of 15-19%. That’s almost half of the state.

Now let’s look at two-candidate-preferred figures. I am using William Bowe’s figures on his website, although I am using the current Labor-Liberal count in Heysen, not an estimated Greens-Liberal count.

At the time of writing, there are 26 Labor-One Nation contests, 13 Labor-Liberal contests, four Liberal-One Nation contests, two independent-One Nation contests, one independent-Labor contest and one independent-Liberal contest.

I will grapple with what a post-election pendulum will look like on another day, likely when we have the final distributions of preferences, but I suspect part of it will be presenting it as Labor vs Liberal/One Nation. If you look at things that way, it covers all but eight seats. Effectively you can see Labor as having two main opponents, with those parties having different strengths in different areas.

I also expect we will be doing a table showing not just the main margin, but an estimated alternative margin (for example, Labor-One Nation and Labor-Liberal) and the margin on the 3CP to change the top two.

So this chart is similar to the first primary vote chart, but it shows the two-candidate-preferred vote in every seat for each party that made that count (so each seat is shown twice). It is easy to identify whether that party won the seat (is their 2CP over 50%?) so instead I have colour-coded based on who the opposing party is.

Again we see that Labor doesn’t have many super-safe seats on huge margins (one on 79.6%, another on 70.9%.

This also can perform some of the same functions as a pendulum. We can see that if there was a 10% swing from Labor to Liberal/One Nation, Labor would lose eight seats to One Nation and four to the Liberal Party. One Nation dominated the Liberal Party in a lot of places where the combined right-wing vote wasn’t enough to win.

Finally, this chart compares 2CP margins before the election (2022 results redistributed for 2026 boundaries) to the results of this election.

The number of conventional marginal seats has shrunk tremendously. On the old boundaries, there were five Labor seats and seven Liberal seats on margins under 4%, with a further six on margins of 4-8%. Now there are just six seats on margins under 4%, with another ten on margins of 4-8%.

The Liberal Party was particularly reliant on marginal seats prior to this election, so it is not surprising that they would lose so many seats.

Sometimes you would expect to see a party that has gained seats to have simply increased its vote everywhere, and thus see seats move to the right on this chart. But Labor hasn’t really gained super-safe seats. They had three seats with margins of 70% or more, and now there are two. They have particularly gained seats in the 8-16% range. Again, this points to remarkable vote efficiency for Labor. They are gaining election-winning numbers in most seats without getting much more than they need.

So let’s go back to the original question – why did Labor win such a huge number of seats? I don’t think much of the story is explained by preferences. There were just four come-from-behind wins. Labor was overtaken by the independent in Kavel and One Nation in Hammond, Labor overtook the Liberal in Morphett and the independent overtook the Liberal (and possibly Labor) in Finniss.

If this was a first-past-the-post election and there was no change in how people voted, Labor would have won 35 seats, the Liberal Party seven, One Nation three and independent two. It’s not much different to the result we will get.

The story here is that Labor was the biggest party, and were fairly efficient at distributing their votes in seats they won and not in any others. In general, they started the count well out in front of their conservative rival (be that One Nation or Liberal) and then gained enough preferences to maintain that lead.

And how solid was that win? It was fairly solid, with Labor not particularly reliant on close marginal seat wins. If there was a uniform swing of 8.7% on the 2CP from Labor to either of the two big right-wing parties, Labor would lose eleven seats. This would leave them with just 23 seats, one short of a majority.

A 10% 2CP swing would be quite big, but I think such a swing would put the state roughly on a 50-50 balance. Across the 39 seats where Labor is in the top two against Liberal or One Nation, the Labor 2CP averages to 59.7%. Once you factor in the very conservative seats where Labor didn’t make the top two, I suspect a Labor 2PP of about 58-59% would be about right. So if a swing of 8.7% leaves Labor just short of a majority, that sounds to be roughly balanced between the left and right.

With just eleven members elected by proportional representation on a statewide vote, most seats were decided quickly just based on primary votes, leaving 1-2 seats in any doubt. At this point the result is clear for all but one seat, with Labor favourites for that seat.

For this blog post I’m going to examine what could happen with the remaining votes to be counted, and with flows of preferences.

Ten seats have definitively been decided: four Labor, three One Nation, two Liberal and one Greens. Nine of these seats are based on the party polling a full quota. One Nation is on 2.92 quotas so we can be confident they will win a third seat.

Labor has a decent lead for the eleventh seat. The remaining quotas for the leading candidates are as follows:

• Labor – 0.44
• Legalise Cannabis – 0.29
• Family First – 0.25
• Greens – 0.22
• Animal Justice – 0.16
• Liberal – 0.12
• Real Change – 0.12
• Others – 0.46

So what changes between now and the final declaration of the result? Two extra pieces of information will be added. Firstly, there are still some primary votes yet to be tallied. Secondly, preferences will be distributed. I’ll deal with those one at a time.

Unfortunately we are dealing with a severe shortage of data when it comes to which votes have been counted, and which ones haven’t, and it’s hard to compare like-with-like compared to the last election.

It is difficult to know precisely which votes have been counted. The ECSA website reports that nearly all election day and pre-poll booths have been counted, and I suspect the missing booths are those that were not actually used (based on examining lower house data). But there is little data on the other vote categories which are currently being counted in the lower house counts, and presumably are in the process of being added in the upper house. About 1.13 million votes were cast in 2022, and about 980,000 votes have been cast this time.

In theory, we could compare the votes cast in 2022 in categories that have been counted, with those yet to be counted. Unfortunately we lack detailed data on which votes have been counted, and ECSA has changed the voting categories enough to make such a comparison impossible anyway. In the 2022 booth results, there is a single ‘declaration votes’ to cover all votes other than ordinary election-day votes including pre-poll and postal votes. That vote category was slightly worse for Labor, significantly worse for the Greens, about the same for One Nation and significantly better for the Liberal Party. But many of those have been counted already this time. Now that ECSA is publishing results in more detail, this task could be easier in 2030 with greater transparency.

So what about preferences? How would we expect them to flow?

This is just the third election in South Australia since the state abolished group voting tickets prior to the 2018 election. This effectively produced a new electoral system and you can’t really compare results before and after the reforms.

In 2018, 60.4% of voters just voted ‘1’ above the line’, while 33.4% numbered multiple preferences above the line and 6.2% voted below the line. In 2022, 62.6% voted just ‘1’ above, 31.3% numbered preferences above the line, and 6.1% voted below the line.

In comparison, New South Wales uses a similar electoral system, and rates of voters just voting ‘1’ above the line was over 80% in 2011 and 2015, but has since dropped to about 60%, in line with South Australia.

So there’s a lot of voters not doing much with their preferences. In theory, we could see rates of preferencing increasing, but South Australia was already in line with New South Wales in 2022.

This new electoral system is yet to produce a result in South Australia where preferences have mattered – in both 2018 and 2022, the candidates leading on primary votes were all elected. Of course, this doesn’t mean that preferences can’t matter, but they tend to play a smaller role in such a high-magnitude election when so many voters opt out of marking preferences.

I have calculated the position of each candidate during the final rounds of the count in 2018 and 2022. ECSA actually reports thousands of counts, showing every batch of votes that are moved, but I have simplified these counts to just show rounds when the distribution of one candidate’s preferences is finalised. For these graphs I show the numbers for the last seven candidates running for the last two seats. I show the round when there is one candidate left for each group, and the counts when just those seven candidates remain.

In 2018, the Liberal and Greens candidates started well in front of the other candidates – the Greens were 0.256 ahead of Labor when each group was still in the race.

The Greens tended to gain the highest rate of preferences. Between count 31 and count 40, the Greens gained 0.191 quotas, Labor gained 0.115, the Liberal gained 0.117 and the Christians gained 0.066.

The contest was much closer in 2022. At the point where there was one candidate left per group, the gap between One Nation (on track for the tenth seat) and the Liberal Democrats (in twelfth place) was just 0.111 quotas. Notably the Greens were not in the hunt in 2022 -the party had gained a swing which put them just over a quota, so the second Greens candidate had a small number of votes to distribute.

Between counts 26 and 35, Labor again gained the largest share of preferences, of 0.087 quotas, with Family First gaining 0.058 and SA Best gaining 0.062.

By the final count, One Nation had gained 0.127, Labor 0.202 and Family First 0.160.

One thing that is consistent here is Labor does relatively well out of preferences, but not as well as the Greens.

So let’s go back to the parties competing for the last seat in 2026. Labor has a big lead, with Legalise Cannabis their closest rival, followed by Family First and the Greens.

I think it is very likely that Labor has too much of a lead to be caught up. I think Legalise Cannabis may do relatively well out of preferences, but it’s a big gap to close. I can’t see the Greens or Family First catching up.