The voice to parliament vote will be the first referendum in Australia since 1999, with Australians asked to vote on the following question:
A Proposed Law: to alter the Constitution to recognise the First Peoples of Australia by establishing an Aboriginal and Torres Strait Islander Voice.
Do you approve this proposed alteration?
Due to the significance of this historic vote, it is important to track support, with at least 10 different polling companies surveying people’s voting intentions.
This first chart records the outcomes of opinion polls on the voice and averages the support over time to track the progress of the yes and no campaigns.
You can read more about the methods below, but it is worth also keeping in mind that in addition to the uncertainty involved in polling due to sample sizes, there are a number of other factors that make measuring the polls even more difficult.
One of the unique features of a constitutional referendum is the requirement for a double majority – that is, to succeed it requires a majority of voters to vote yes nationally, and it requires a majority in a majority of states, so four out of the six states must have a majority yes vote.
-
Sign up for Guardian Australia’s free morning and afternoon email newsletters for your daily news roundup
This presents another difficulty in tracking the likelihood of success of the voice via polling, as few national polls so far have surveyed enough people to get a decently sized sample of voters from all of the six states, with South Australia, Western Australia and Tasmania in particular having low numbers.
This table records recent polls with state-level results, divided into those that allow a “don’t know” response and those that do not. The latter will of course have a higher percentage value for the yes percentage.
Here, you can see the support for the voice to parliament by state from the most recent Essential poll, along with a measure of the margin of error.
This chart shows support for the voice by voting intention, again from the most recent Essential poll. Polling consistently shows a divide along party voting lines, with Labor and Greens supporters more likely to say they will support the voice, while Coalition voters are more likely to be opposed.
A similar divide emerges in age groups, with younger people far more likely to say they will vote yes.
Voice poll averaging methods
-
New national polls are added to the data as they are released. The last day of data collection is used for sorting.
-
Where polls report the share of undecided voters, undecided voters have been removed and the yes/no share recalculated to give a binary yes/no response.
-
A generalised additive model is fit to the adjusted, binary polling data.
-
Smoothing parameters for the model are estimated using restricted maximum likelihood.
-
The model is weighted using the sample sizes of the individual polls.
-
The GAM model is used to generate a trend line, along with a 95% confidence interval.