A referendum to change the Constitution is always an up-hill battle, requiring the support of not only the majority of voters but also the majority of voters in the majority of states. Only 8 of our 44 Referenda have been successful—18%. It’s also an uncommon event—the last referendum was in 1999, meaning this is the first time voting in one for anyone under the age of 42.
This means that there is VERY little data to draw from, but we do know that on balance the NO campaign has the advantage.
Polling
Superficially, polling indicates that the NO vote will be in the majority, which would prevent constitutional change. That is widely the consensus, and no poll has placed the YES vote ahead since July.
For the following analysis, polls are dated by the last day of polling. Polls without a published end date are not included. Polls prior to the last federal election (21 May 2022) and announcement that a Voice would be pursued by the Albanese government are also excluded.
There has been a noticeable increase in support for the NO campaign over time, drawing from both the undecideds and YES voters. What started at less than 20% of the population now consistently commands over 50% of the vote, meaning that on these numbers even if all undecideds break for YES, the NO campaign would succeed.
We can break this down by polling house. For this analysis I have excluded sources who (1) have not released a poll in the last month, as this is difficult to extrapolate to the current results and (2) have published less than three polls on the referendum since 21 May 2022. This leaves seven firms: Essential (7 polls), Freshwater Strategy (5 polls), JWS Research (4 polls), Newspoll (10 polls), Resolve Strategic (9 polls), Roy Morgan (6 polls) and YouGov (3 polls).
What we see, interestingly, is that there is not a huge distinction between the polling houses: all methods seem to converge on similarly clustered results and trends. These, by their latest polls put the YES campaign at between 33% and 44% and NO between 49% and 57%. Undecideds are anywhere between 5% (Roy Morgan) and 17% (Freshwater Strategy) of the vote.
To succeed just for the vote of the total population, YES would need to take the most favourable of these offerings and win virtually 100% of the undecided vote. In reality, the existing polling shows if anything that undecideds tend to break in favour of the NO campaign (possibly as a result of the “Don’t know? Vote NO!” slogan).
If we compare the YES share of divided votes (that is, YES/(YES+NO) x 100%) to the undecideds, we find this sharply illustrated.
Extrapolating the trend line to 0% undecided, this would have the YES vote at around 13.5% of the decided votes (i.e. a NO vote of 86.5%). This seems unrealistically high, but emphasises the difficulty that YES has of securing the undecided vote.
The reason this seems unrealistic is likely because it also factors in a significant decay in the YES vote over time. It assumes that if we allowed the undecideds to resolve the YES decline would also continue. But polling day requires the undecided vote to resolve immediately which does not allow for the continued erosion of the YES vote. (Also, presumably there is a floor below which the YES vote will not drop, but that is only relevant for a gradual resolution of undecideds).
Returning to the first graph in this post, we see that the drop in YES and undecided votes is roughly the same: a rate of 0.03 percentage points per day for undecideds and 0.04 for YES. At the extremes of possibility this could reflect 0.03 pp/day from undecideds and 0.04 pp/day form YES to NO, or 0.03 pp/day from undecideds to YES and 0.07 pp/day from YES to NO. The reality is probably a break somewhere between these, with some transfer form undecided to both camps, and some YES moving to NO. Assuming NO is winning over a larger share of undecideds just as they are winning over more YES, and preferring rounder numbers, we take a wild guess that:
0.01 pp/day undecideds move to YES.
0.02 pp/day undecideds move to NO.
0.05 pp/day YES mover to NO.
This is a 2:1 split of undecideds in favour of NO based on basically nothing, but would give the NO vote something like 57% of the vote--towards the upper end of polling.
PREDICTION: NO wins the popular vote.
States
We have state-by-state polling, and we could make similar unfounded assumptions about the undecideds, but the key question is which state falls which way.
New South Wales polling has favoured NO in 7 of the 8 polls in the last month
Victoria has favoured NO in 6 of the 8 polls in the last month
Queensland has favoured NO in 9 of the 9 polls in the last month
Western Australia has favoured NO in 5 of the 5 polls in the last month
South Australia has favoured NO in 5 of the 5 polls in the last month
Tasmania has favoured NO in 2 of the 2 polls in the last month
On this rating, the states ordered from most to least likely to vote YES are:
TAS Vic NSW WA/SA Qld
Two polls concluded on October 12. For the Newspoll, the states ordered from strongest to weakest support to YES are:
Vic NSW Tas SA Qld WA
For Roy Morgan, the states ordered from strongest to weakest support to YES are:
Vic NSW Tas WA SA Qld
Compiling this data, the most winnable states for YES look to be Victoria, New South Wales and Tasmania, with Queensland the hardest to win. YES will need all three plus either SA or WA.
PREDICTION: The states will resolve in the following order of support:
Vic: YES (Strongest YES vote)
NSW: NO
Tas: NO
SA: NO
WA: NO
Qld: NO (Strongest NO vote)
Summary of Predictions
The YES campaign will fail decisively on both the popular and state counts.
The NO vote nationally will sit at around 57%.
Victoria will be the strongest YES voting state, and Qld the least.
