Mackerras pendulum for the next Australian federal election
This is a Mackerras pendulum for the next Australian federal election.
History
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 crossbench according to the percentage-point margin they are held by on a two-party or two-candidate 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]
Pendulum
Based on the 2013 post-election pendulum for the Australian federal election and changes since, this 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 redistributions reduced the Liberal/National Coalition from 90 to a notional 88 seats and increased Labor from 55 to a notional 57 seats. Assuming a uniform swing, the Coalition can retain office despite losing 12 seats on a two-party swing of 3.2%, while Labor would need to gain 19 seats on a uniform two-party swing of 4.0% for majority government. The Coalition won 53.5% of the two-party vote at the previous election.[2]
See also
Notes
a Though the seats of Dobell, Paterson and Barton were Liberal wins at the previous election, redistributions changed them in to notionally marginal Labor seats.[2]b Pat Conroy is the current MP for the Division of Charlton which is being renamed to the Division of Hunter at the next election.
References
- ↑ "Division Classifications – House of Representatives - Seat Summary", Virtual Tally Room 2013, Australian Electoral Commission. Retrieved 30 October 2013.
- 1 2 2016 Federal Election Pendulum (Update): Antony Green ABC 13 March 2016