Australia is one of the few countries where voters number every candidate in order. Here’s how preferential voting works, how preferences decide close seats, and why parties fight over them.
Australia uses preferential voting, also known as instant-runoff voting, for elections to the House of Representatives, the house where government is formed.
Instead of ticking one box, voters number all the candidates in order of preference, putting 1 next to their first choice, 2 next to their second choice, and so on.
Preferential voting was introduced for federal elections in 1918. Voting has been compulsory in Australia since 1924.
How the count works
First, all the number 1 votes, known as first preferences, are counted. If a candidate gets more than 50% of them, they win.
If no one has a majority, the candidate with the fewest votes is eliminated, and their ballots are passed on to whichever remaining candidate each voter numbered next. The process repeats until one candidate has more than 50%.
That means a candidate who didn’t come first on the first count can still win the seat with preferences from other candidates.
Why it matters
Under preferential voting, voters can support a minor party or independent as their first choice, without “wasting” their vote. If that candidate is eliminated, the vote flows to their next choice.
That’s helped independents and minor parties, such as the Greens and community independents, win seats in recent elections, because they can overtake a major party candidate with preferences from others.
Two-party preferred
Because most seats come down to a contest between Labor and the Coalition, results are often expressed as a two-party preferred vote. That’s the share of the vote each major party gets after all preferences are distributed between just those two.
Opinion polls usually report a two-party preferred figure, which is generally seen as the best guide to who’ll win government.
How-to-vote cards and preference deals
Parties hand out how-to-vote cards at polling places, suggesting how their supporters should number the ballot. They often negotiate with each other over who to recommend.
Voters don’t have to follow how-to-vote cards. The voter alone decides where their preferences go.
The Senate is different
Senate elections use a different system, called proportional representation, where voters can number parties above the line or candidates below it, and candidates win seats by reaching a quota of votes.
Some states use variations of preferential voting for their own elections. In New South Wales and Queensland, for example, voters can choose to number only one candidate.
