I don’t intend to talk much about politics on this blog, but in this case I’ll make an exception. Australia will have its 43rd federal election on the 21st, and I am a first-time voter. In a follow-up post either later today or tomorrow, I’ll get into a bit of politics — and given the subject matter of my blog, I’ll mostly be talking about climate policy — but for now, a bit of background about, and analysis of, the Australian electoral system.
Voting is compulsory, though it’s a secret ballot so voters are free to “vote informally” by leaving their ballot paper blank or incorrectly filled in. There are two houses of Parliament: the lower house is called the House of Representatives, and the upper house is the Senate. The House has 150 members, who serve three-year terms and are elected from single-member electorates. Each electorate is supposed to contain more or less the same number of voters (though the rules are complicated, and in practice the number can vary from around 60,000 to around 120,000).
In House of Representatives elections, Australia uses a preferential voting system called instant-runoff voting. Voters must number all the candidates on the ballot paper in order of their preference. If one candidate receives more than 50% of the first-preference votes then they are declared elected. If not, the candidate with the least votes is eliminated and their votes are redistributed according to the second preferences of each person who voted for that candidate. This process continues until one candidate passes the 50% benchmark. Continue reading