Post-election pendulum for the 2001 Australian federal election

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The Mackerras pendulum 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 instant-runoff voting.

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. [1]

Government seats (82)
Marginal
Hinkler Qld Paul Neville NAT0.04
Solomon NT Dave Tollner CLP0.09
Farrer NSW Sussan Ley LIB0.14 v NAT
Adelaide SA Trish Worth LIB0.22
Dobell NSW Ken Ticehurst LIB0.38
Canning WA Don Randall LIB0.38
Parramatta NSW Ross Cameron LIB1.15
McEwen Vic Fran Bailey LIB1.20
Paterson NSW Bob Baldwin LIB1.42
Herbert Qld Peter Lindsay LIB1.62
Richmond NSW Larry Anthony NAT1.68
Eden-Monaro NSW Gary Nairn LIB1.69
Deakin Vic Phil Barresi LIB1.74
Hindmarsh SA Chris Gallus LIB1.86
Longman Qld Mal Brough LIB2.72
Page NSW Ian Causley NAT2.77
Petrie Qld Teresa Gambaro LIB3.42
La Trobe Vic Bob Charles LIB3.67
Makin SA Trish Draper LIB3.76
Moreton Qld Gary Hardgrave LIB4.21
Kalgoorlie WA Barry Haase LIB4.34
Cowper NSW Luke Hartsuyker NAT4.73
Dunkley Vic Bruce Billson LIB5.42
Lindsay NSW Jackie Kelly LIB5.47
Corangamite Vic Stewart McArthur LIB5.67
Warringah NSW Tony Abbott LIB5.67 v IND
Dickson Qld Peter Dutton LIB5.97
Fairly safe
Moore WA Mal Washer LIB6.04
Aston Vic Chris Pearce LIB6.17
Leichhardt Qld Warren Entsch LIB6.39
Pearce WA Judi Moylan LIB6.87
Robertson NSW Jim Lloyd LIB6.98
Casey Vic Tony Smith LIB7.16
Boothby SA Andrew Southcott LIB7.35
Forde Qld Kay Elson LIB7.38
Forrest WA Geoff Prosser LIB7.61
Flinders Vic Greg Hunt LIB7.62
Bennelong NSW John Howard LIB7.70
Wentworth NSW Peter King LIB7.86
Tangney WA Daryl Williams LIB7.97
Dawson Qld De-Anne Kelly NAT7.99
Gippsland Vic Peter McGauran NAT8.02
Sturt SA Christopher Pyne LIB8.18
Higgins Vic Peter Costello LIB8.39
Blair Qld Cameron Thompson LIB8.50
Ryan Qld Michael Johnson LIB8.62
Macquarie NSW Kerry Bartlett LIB8.67
Parkes NSW John Cobb NAT8.74
Menzies Vic Kevin Andrews LIB8.94
Fairfax Qld Alex Somlyay LIB9.21
Goldstein Vic David Kemp LIB9.48
Wannon Vic David Hawker LIB9.58
Hume NSW Alby Schultz LIB9.79
Macarthur NSW Pat Farmer LIB9.96
Safe
Hughes NSW Danna Vale LIB10.41
Grey SA Barry Wakelin LIB10.56
Wide Bay Qld Warren Truss NAT10.73
Kooyong Vic Petro Georgiou LIB10.94
Indi Vic Sophie Panopoulos LIB11.19
Lyne NSW Mark Vaile NAT11.24
Fisher Qld Peter Slipper LIB12.06
Fadden Qld David Jull LIB12.29
McPherson Qld Margaret May LIB12.55
Mayo SA Alexander Downer LIB12.87
North Sydney NSW Joe Hockey LIB13.21
Curtin WA Julie Bishop LIB13.91
Cook NSW Bruce Baird LIB14.00
Wakefield SA Neil Andrew LIB14.57
Gilmore NSW Joanna Gash LIB14.63
Gwydir NSW John Anderson NAT14.88
Groom Qld Ian Macfarlane LIB15.09
Moncrieff Qld Steven Ciobo LIB15.42
Berowra NSW Philip Ruddock LIB15.65
Barker SA Patrick Secker LIB15.69
Maranoa Qld Bruce Scott NAT16.01
Mackellar NSW Bronwyn Bishop LIB16.87
O'Connor WA Wilson Tuckey LIB19.09
Mallee Vic John Forrest NAT19.93
Very safe
Bradfield NSW Brendan Nelson LIB21.16
Mitchell NSW Alan Cadman LIB21.32
Murray Vic Sharman Stone LIB23.93
Riverina NSW Kay Hull NAT29.88
Opposition seats (65)
Marginal
Bowman Qld Con Sciacca ALP1.42
Stirling WA Jann McFarlane ALP1.58
Hasluck WA Sharryn Jackson ALP1.78
Swan WA Kim Wilkie ALP2.04
Bass Tas Michelle O'Byrne ALP2.06
Kingston SA David Cox ALP2.42
McMillan Vic Christian Zahra ALP2.46
Ballarat Vic Catherine King ALP2.73
Chisholm Vic Anna Burke ALP2.77
Isaacs Vic Ann Corcoran ALP2.81
Bank NSW Daryl Melham ALP2.88
Greenway NSW Frank Mossfield ALP3.11
Brisbane Qld Arch Bevis ALP3.13
Bendigo Vic Steve Gibbons ALP3.57
Lowe NSW John Murphy ALP3.81
Lilley Qld Wayne Swan ALP4.83
Lingiari NT Warren Snowdon ALP5.29
Cowan WA Graham Edwards ALP5.51
Burke Vic Brendan O'Connor ALP5.51
Bruce Vic Alan Griffin ALP5.55
Jagajaga Vic Jenny Macklin ALP5.64
Griffith Qld Kevin Rudd ALP5.66
Melbourne Ports Vic Michael Danby ALP5.69
Braddon Tas Sid Sidebottom ALP5.96
Fairly safe
Barton NSW Robert McClelland ALP6.02
Charlton NSW Kelly Hoare ALP6.66
Rankin Qld Craig Emerson ALP6.68
Capricornia Qld Kirsten Livermore ALP6.86
Newcastle NSW Sharon Grierson ALP6.91
Franklin Tas Harry Quick ALP8.04
Oxley Qld Bernie Ripoll ALP8.14
Lyons Tas Dick Adams ALP8.17
Werriwa NSW Mark Latham ALP8.49
Corio Vic Gavan O'Connor ALP8.70
Shortland NSW Jill Hall ALP8.78
Kingsford Smith NSW Laurie Brereton ALP8.90
Canberra ACT Annette Ellis ALP9.44
Safe
Brand WA Kim Beazley ALP10.05
Bonython SA Martyn Evans ALP10.42
Cunningham NSW Stephen Martin ALP10.65
Fremantle WA Carmen Lawrence ALP10.72
Hunter NSW Joel Fitzgibbon ALP10.86
Hotham Vic Simon Crean ALP11.01
Perth WA Stephen Smith ALP11.21
Prospect NSW Janice Crosio ALP12.81
Fraser ACT Bob McMullan ALP12.96
Holt Vic Anthony Byrne ALP13.32
Denison Tas Duncan Kerr ALP14.26
Port Adelaide SA Rod Sawford ALP14.65
Sydney NSW Tanya Plibersek ALP15.04
Throsby NSW Jennie George ALP15.10
Blaxland NSW Michael Hatton ALP15.21
Chifley NSW Roger Price ALP15.29
Lalor Vic Julia Gillard ALP15.63
Reid NSW Laurie Ferguson ALP16.87
Watson NSW Leo McLeay ALP17.31
Maribyrnong Vic Bob Sercombe ALP17.38
Calwell Vic Maria Vamvakinou ALP17.73
Scullin Vic Harry Jenkins ALP19.17
Wills Vic Kelvin Thomson ALP19.42
Very safe
Melbourne Vic Lindsay Tanner ALP20.09
Grayndler NSW Anthony Albanese ALP21.29
Fowler NSW Julia Irwin ALP21.50
Gellibrand Vic Nicola Roxon ALP21.78
Batman Vic Martin Ferguson ALP25.08
Crossbench seats (3)
New England NSW Tony Windsor IND8.30 v NAT
Kennedy Qld Bob Katter IND19.73 v ALP
Calare NSW Peter Andren IND25.04 v NAT

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The following is a pendulum based on the outcome of the 2010 federal election and changes since, including the redistributions of seats in South Australia and Victoria. It is a Mackerras pendulum, invented by psephologist Malcolm Mackerras, which works by lining up all of the seats held in Parliament according to the percentage point margin on a two-candidate-preferred basis. The two-party result is also known as the swing required for the seat to change hands. Given a uniform swing to the opposition or government parties in an election, the number of seats that change hands can be predicted. Swings are never uniform, but in practice variations of swing among the Australian states usually tend to cancel each other out. Seats are arranged in safeness categories according to the Australian Electoral Commission's (AEC) classification of safeness. "Safe" seats require a swing of over 10 per cent to change, "fairly safe" seats require a swing of between 6 and 10 per cent, while "marginal" seats require a swing of less than 6 per cent. The swings for South Australian and Victorian seats are notional, based on calculations by the AEC.

The Coalition won the 2013 federal election with 90 of 150 lower house seats on a current 17-seat, 3.65-point two-party swing, defeating the 6-year Labor government. Labor holds 55 seats while crossbenchers hold the remaining five. The Division of Fairfax was the last seat to be declared.

This is a Mackerras pendulum for the 2016 Australian federal election.

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The Labor party won the 2018 state election by winning 55 of the 88 lower house seats. The coalition won 27 seats while the Greens and independents won 3 each.

The Coalition won the 2019 federal election with a three-seat majority of 77 of 151 lower house seats. Labor holds 68 seats, and crossbenchers hold the remaining six.

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.

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The Mackerras pendulum 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 instant-runoff voting.

The Mackerras pendulum 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 instant-runoff voting.

The Mackerras pendulum 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 instant-runoff voting.

References

  1. Sakkal, Paul; Rooney, Kieran (14 November 2023). "Veteran Liberal Party MP Russell Broadbent quits party, moves to crossbench". The Sydney Morning Herald.