Election preferences: do you need to think strategically before voting in the lower house?

The increasing number of credible campaigns from independents in the federal election is making for some intriguing contests, and in some seats may raise questions for voters about where to place their preferences, as well as their primary vote.

On election night, votes are tallied up according to the first preference, or primary vote. Once all the votes have been counted, preferences are distributed. The candidate with the fewest first-preference votes is eliminated, and their votes are distributed to the next preference, and so on until only two candidates remain.

In most cases it is clear on election night who those two candidates will be, so a special count is conducted just between these two candidates, without having to wait for all the votes to be counted before a full distribution of preferences.

In some seats, the order of elimination can determine whether the second-placed candidate gains enough preferences to catch the leading candidate, and thus can change the ultimate outcome.

But there are also races where the preference flows are not symmetrical. This is most common when there is an independent competing with a Labor candidate, both vying to make it to the final count against a Coalition candidate.

A recent example was in the seat of Warringah in 2019, where the independent candidate Zali Steggall won 57.2% of the two-candidate-preferred count against Tony Abbott. The Australian Electoral Commission also conducted a count between the Liberal and Labor candidates, with the Labor candidate receiving just 47.9%. That means 9.3% of voters in Warringah preferred Steggall over Abbott, but preferred Abbott over Labor.

Some have called for voters to consider casting a strategic vote in this way.

I think voters should instead stick to a principled vote: number your ballot paper in the order of your genuine preference.