A federal election to determine all 226 members of the 45th Parliament of Australia will take place on Saturday 2 July 2016 after an extended eight-week official campaign period. It is the first double dissolution since the 1987 election. Elections in Australia use a full-preferential system in one vote, one value single-member seats for the 150-member House of Representatives (lower house) and is changing from full-preferential group voting tickets to an optional-preferential single transferable vote system of proportional representation in the 76-member Senate (upper house). Voting is compulsory.
By Westminster convention, but subject to constitutional constraints, the decision as to the type of election and its date is for the prime minister, who advises the governor-general to set the process in motion by dissolving the lower or both houses and issuing writs for election. As of the close of nominations on 9 June 2016, there are 1,625 candidates in total – 994 for the House of Representatives and 631 for the Senate. The number of Senate candidates is the highest ever at an Australian election, increasing from 529 in 2013.
Based on the 2013 post-election pendulum for the Australian federal election, this Mackerras pendulum has been updated to include new notional margin estimates due to redistributions in New South Wales, Western Australia and the Australian Capital Territory. The net effect of the redistributions reduced the Liberal/National Coalition from 90 to a notional 88 seats and increased Labor from 55 to a notional 57 seats. While every federal election after 1961 has been won by those that also won the majority of federal seats in New South Wales, unusually nearly half of all marginal government seats are in New South Wales at this election, of which nearly half are in Western Sydney and the other half in rural and regional areas, and with no more than a few seats each in every other state.
