The Liberal-National Coalition win in the 2019 Australian federal election came as a surprise to the nation. The media and the polls had provided a consistent narrative in the lead up to election day that Labor was headed for victory. When we have unexpected election results, how do we make sense of why people voted the way they did? The Australian Election Study (AES) provides the most sophisticated and comprehensive source of evidence ever collected on political attitudes and behaviour in Australia. A representative public opinion survey, the AES has been fielded after every federal election since 1987. The survey asks a wide range of questions to discover what shaped voters’ choices at the ballot box—including considerations in the vote decision, the importance of different policy issues, and attitudes towards the political parties and leaders. This provides a wealth of information to understand voter behaviour and how that feeds into election results.