 2025 Australian federal election |
|---|
| National results |
| State and territory results |
The Mackerras pendulum was devised by the Australian psephologist Malcolm Mackerras as a way of predicting the outcome of an election contested between two major parties in a Westminster style lower house legislature such as the Australian House of Representatives, which is composed of single-member electorates and which uses a preferential voting system such as a Condorcet method or IRV.
The pendulum works by lining up all of the seats held in Parliament for the government, the opposition and the crossbenches according to the percentage point margin they are held by on a two party preferred basis. This is also known as the swing required for the seat to change hands. Given a uniform swing to the opposition or government parties, the number of seats that change hands can be predicted.
Classification of seats as marginal, fairly safe or safe is applied by the independent Australian Electoral Commission using the following definition: "Where a winning party receives less than 56% of the vote, the seat is classified as 'marginal', 56–60% is classified as 'fairly safe' and more than 60% is considered 'safe'." [1]
Some margins may differ from the results at the 2022 federal election or by-elections that have occurred following that election. In these cases, the margins used have been predicted (by Antony Green) based on the new boundaries following redistributions in New South Wales, Victoria, and Western Australia. [2] The newly created Division of Bullwinkel is also included on this pendulum with a predicted margin as no election results yet exist for the division.
Listed below are the elected members at the time of the election, with those italicised having announced their retirement.
| Crossbench seats (15) | ||||
| Greens seats - 4 | ||||
| Marginal | ||||
| Ryan | Qld | Elizabeth Watson-Brown | GRN vs. LNP | 2.6 |
| Brisbane | Qld | Stephen Bates | GRN vs. LNP | 3.7 |
| Fairly Safe | ||||
| Melbourne | Vic | Adam Bandt | GRN vs. ALP | 6.5 |
| Safe | ||||
| Griffith | Qld | Max Chandler-Mather | GRN vs. LNP | 10.5 |
| Other Crossbench - 11 | ||||
| Marginal | ||||
| Fowler | NSW | Dai Le | IND vs. ALP | 1.1 |
| Curtin | WA | Kate Chaney | IND vs. LIB | 1.3 |
| Kooyong | Vic | Monique Ryan | IND vs. LIB | 2.2 |
| Goldstein | Vic | Zoe Daniel | IND vs. LIB | 3.3 |
| Mackellar | NSW | Sophie Scamps | IND vs. LIB | 3.3 |
| Fairly safe | ||||
| Wentworth | NSW | Allegra Spender | IND vs. LIB | 6.8 |
| Indi | Vic | Helen Haines | IND vs. LIB | 8.9 |
| Warringah | NSW | Zali Steggall | IND vs. LIB | 9.4 |
| Safe | ||||
| Mayo | SA | Rebekha Sharkie | CA vs LIB | 12.3 |
| Kennedy | Qld | Bob Katter | KAP vs LNP | 13.1 |
| Clark | Tas | Andrew Wilkie | IND vs ALP | 20.8 |
