Explaining voting in the 2017 Australian same-sex marriage plebiscite

The 2017 Australian Marriage Law Postal Survey led to the adoption of same-sex marriage. Using ecological analysis, this paper tests five hypotheses to explain voting in the plebiscite. Social characteristics exerted a strong influence on the vote, with a higher ‘yes’ vote in more affluent and suburban electorates, and a higher ‘no’ vote in electorates with large numbers of traditional households. The strongest predictor of a ‘no’ vote was electorates with large proportions of newly arrived immigrants. Electorates that had larger proportions of female same-sex couples displayed a higher ‘yes’ vote. Higher turnout in the plebiscite benefitted the ‘yes’ vote. Finally, the views of the local MP on the issue were positively related to the result in their electorate.