 Opinion polls in the lead up to the election consistently understated support for Labor government and overstated support for Liberal/National opposition.Poll aggregation site Poll Bludger placed the two-party-preferred vote for Labor at 53.5%, coupled with primary vote shares at 41.0% for Labor, 39.8% for the Liberal/National Coalition, and 11.1% for the Greens.Election Analyst Antony Green stated on the ABC's election coverage that the result was "four to five percent better than all the opinion polls, which is the most out I've seen opinion polls in this country"

The Liberal Party wrote in their campaign review that their data gathered in their internal research in marginal seats was "fundamentally wrong", which lead to resources and campaigners being diverted from marginal Liberal-held seats to "target "Labor" seats on the false assumption that "[the Liberal Party] had already won [Liberal held] seats".