Saturday, June 25, 2022

Poll performance - 2022 Australian Federal Election

Now that the count is complete we can look at the performance of the final polls immediately prior to the 2022 Australian Federal Election. In terms of the final two party preferred (TPP) outcome, in which Labor won 52.13 per cent of that vote, all of the final polls performed well. The final estimates of TPP voting intention were all well within the margin of error. This is a substantial improvement on performance in 2019.

However, there was some patchiness among the these final polls when it came to estimating the first preference primary votes for each of the major parties. Only the final poll from Resolve Strategic had each primary vote estimate within the 2-sigma margin of error when compared with the election result. The other polls had a tendency to over-estimate Labor's primary vote share and/or under estimate the vote for one or more of the minor parties and independents.

We can sum the absolute values of the differences between the final poll estimate for each party from each pollster and the election outcome, to rank the performance of these final polls in terms of providing an estimate of the election outcome. 

Cautionary Note: This poll ranking should not be seen as a ranking of the pollsters. We expect polls to be randomly distributed around a mean. If we assume ceteris paribus, then then it is just luck (or randomness) as to whether the final poll from one pollster would be closer to the election result or not (when compared with another pollster).

Also note: where pollsters have provided an effective sample size (ESS), this was used to calculate the margin of error. Otherwise the reported sample size was used. 

Link: the Jupyter Notebook for these charts can be found here.

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