YouGov has delivered the most accurate polling of the recent South Australian state election, correctly estimating the primary vote shares of all three major parties to within one percentage point and was the only pollster to do so.

YouGov’s final poll, conducted March 9–17, closely matched the official statewide primary vote with an average difference from the final result of only 0.9%:

Why YouGov was the most accurate

YouGov’s accuracy was driven by its unique data-led methodology, incorporating:

  • Verified past federal vote behaviour
  • Class identification (working class, middle class, well-off)

These inputs allow YouGov to build highly representative samples and capture shifts in voter behaviour that other polling methods can miss.

Polling in an unprecedented election

Accurate forecasting was particularly challenging in this election due to historically unusual outcomes:

  • The Labor Party secured the highest share of seats in its history in South Australia (since 1891).
  • The Liberal Party recorded its lowest vote share in any state or federal election in which it contested every seat.
  • One Nation finished second in the primary vote for the first time since its founding in 1997.

The role of verified past vote data

Following the most recent federal election, YouGov surveyed its entire panel to record how individuals voted while recall was still fresh.

This verified past vote data is used as a quota in sampling, alongside census benchmarks, ensuring accurate representation.

This approach is particularly important in addressing false recall, which has increased with the rise of One Nation. Many voters who previously supported the Coalition or minor right parties now incorrectly report having voted for One Nation in the 2025 Federal election.

Because YouGov has validated historical data, it can correct for this effect and produce more reliable results.

Understanding class and voter behaviour

YouGov is the only pollster in Australia to consistently measure self-identified by class, providing deeper insight into electoral dynamics.

This enabled YouGov to identify key trends, including:

  • Labor losing working-class voters to One Nation
  • Labor gaining middle-class voters from the Liberals
  • Strong One Nation performance in Adelaide’s working-class northern suburbs
  • Labor winning Blue Ribbon Liberal Adelaide electorates for the first time.

For further information, contact Paul Smith, Director of Public Data on paul.smith@yougov.com or Amir Daftari Director, Data Science on amir.daftari@yougov.com

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