The vote count is now getting to a point where pretty much all primary votes have been counted, even if we don’t have all of the preference counts yet. So that means we can now begin to analyse the informal voting trends – where it went up or down, and what some of the causes could be.
I also wanted to look into a story that appeared yesterday in the Sydney Morning Herald which claimed that there had been a surge in informal rates in voting at special hospital booths in 2025, but seemed to be mostly focused on a handful of seats.
Right now the informal rate has increased from 5.2% in 2022 to 5.6%. This would be the second highest rate on record, but only just ahead of the rates at two other elections.
The first thing to check is how the informal rate compares to the size of the ballot paper.
There is a very clear relationship, but there is some nuance worth noting.
There is obviously variation at each level – ballot size doesn’t explain all differences in informality. The most obvious difference is that NSW has higher rates of informality for any given ballot size, and that is particularly true for seats in Western Sydney. Past research has identified communities with more voters of non-English speaking backgrounds as having higher informal rates. The chart above shows how McMahon, Macarthur, Blaxland, Fowler, Chifley and especially Werriwa and Watson stand out from the pack.
The previous record for the highest informal rate in a seat was Scullin in 1984, with 14.09%. Fowler came close to this level, and Werriwa and Watson easily broke the record.
The uptick in the informal rate particularly appears when you get to eight candidates on the ballot. This has been noticeable since the change in the Senate electoral system in 2016, which introduced the recommendation that voters number at least 1 to 6. If you follow those instructions in the House of Representatives, your vote will be formal on a ballot paper with no more than 7 candidates, but informal on a larger ballot.
Next up, I wanted to look at how the change in the informal rate compares to the change in the size of the ballot. In the case of redistributions, I have weighted the 2022 ballot size to the parts of each old electorate. So, to take an example, the seat of Bradfield had 7 candidates, and North Sydney had 10 candidates. Just over a quarter of the new Bradfield came from North Sydney, so I give it a score of 7.8.
The relationship is even stronger than with the current size of the ballot paper and informal rate. Overall the national enrolment rate increased, but so did the average ballot paper size. Four Western Sydney seats stand out as having even more of an increase of their informal rate than the change in ballot size would suggest.
If this theory is correct, there is not necessarily any change to voter behaviour driving higher informal rates – it’s a natural consequence of increasing numbers of candidates making the act of voting under our electoral system more difficult. But that clearly doesn’t explain everything.
With Bradfield being so close, there has been a lot of interest in that seat. This led me to mapping out the change in informal vote across Bradfield, and for reasons that will become clear in a minute, to also do the same for the two other seats which took in parts of North Sydney.
Bradfield and Mackellar each had seven candidates in 2022, in the range where a 1-6 vote is formal. Bennelong had eight candidates, and North Sydney had ten. All three seats had eight candidates this year.
This means that all three seats have taken in areas that previously had an 8+ ballot paper, while the remainder of Bradfield and Mackellar had an under-8 ballot paper.
This ends up being very obvious on the map. I’ve highlighted the former boundaries of North Sydney in light blue.
When you look at the booths of Bradfield, there is a clear trend where the informal vote has increased in the areas already part of Bradfield, but not in the former North Sydney. The same trend can be seen in Warringah, but less so in Bennelong which already had a ballot of eight in 2022.
There is one interesting theory about some of these increases in informality, which is due to the emergence of new groups publishing how-to-vote cards, whether it is a teal independent like Nicolette Boele, who issued a how-to-vote card that would be informal if a voter copied it exactly, or added complexity in seats like Blaxland, Watson and Werriwa where Labor’s domination has been challenged. I can’t prove this theory, but I think it’s interesting.
The AEC was asked about informal votes in yesterday’s media briefing and they confirmed that there will be a survey of informality following this election. I believe this was last conducted following the 2016 election, and yielded very useful data on the exact ways in which voters marked ballots that ended up informal.
Finally, I have attempted to holistically analyse informal rates amongst special hospital teams – how high the rates typically are, and how much they have changed. The SMH story appears to have focused on particular electorates, but with such small numbers of voters you could expect particular booths to bounce around even if the national trend doesn’t change much.
The first thing to note is that hospital voting basically did not exist in 2022. While about 80-90,000 votes were cast in 2016, 2019 and 2025, it was just 4,000 votes in 2022. So it is fairer to compare 2025 to 2019, which the SMH story did.
Special hospital teams has historically been one of the types of voting with a higher rate of informal voting. The rate has increased, from 7.3% in 2019 to 10.5% in 2022. That rate has been repeated in 2025. So yes, the informal rate has gone up, but by nowhere near the rates suggested in the Herald story.
Bradfield in 2019 had over 1,000 hospital votes cast, with an informal rate of just 1.6%. This is compared to an informal rate of 16% in 2025.
But that 2019 statistic was an extreme outlier. Excluding two seats where a very small number of hospital votes were cast and no informal votes were included in them, Bradfield had the lowest rate in the country. The 2025 rate is also quite high, but not right at the top. Twenty other seats had a higher informal rate than Bradfield amongst the hospital booths in 2025.
So yes, there has been an increase in informal voting in the hospital booths, but most seats have not seen an increase anywhere near as big as Bradfield, which partly looks bad because it had such a remarkable result in 2019.
When a race is coming down to the wire like it is in Bradfield, any factor can be enough to tilt the result. But I don’t see a reason to think that informal voting in the hospital booths is a national problem or is significantly worse than it was in the past.