How good are the polls? Australian election predictions, 1993–2019

ABSTRACT None of the polls predicted the winner of the 2019 Australian election, the first such failure since 1993 when all the polls started reporting a two-party preferred (2PP) vote estimate of the vote share as well as the parties’ first preferences. But the idea that the polls had enjoyed a very good run until 2019 is misleading: from 1993 to 2016, a fifth had predicted the wrong winner. This paper examines the performance of the polls against several measures: the outcome; margins of error; size of the errors; and estimates of the gap between the Liberal-National Party (LNP) and Labor. It shows that about a third of the estimates of the 2PP vote, Labor’s first preferences, and the LNP’s first preferences, involved errors greater than those attributable to sampling error.