Pre-election pendulum for the 2025 Australian federal election

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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 are predictions (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.

The names listed in the tables refer to the currently elected members. Members in italics have announced their retirement at this election.

Government seats (78)
Marginal
Bennelong NSW Jerome Laxale ALP-0.1
Gilmore NSW Fiona Phillips ALP0.17
Lyons Tas Brian Mitchell ALP0.92
Lingiari NT Marion Scrymgour ALP0.95
Robertson NSW Gordon Reid ALP2.27
Paterson NSW Meryl Swanson ALP2.6
Tangney WA Sam Lim ALP2.8
Chisholm Vic Carina Garland ALP3.2
Bullwinkel WANew division(Notional) ALP3.3
McEwen Vic Rob Mitchell ALP3.4
Parramatta NSW Andrew Charlton ALP3.7
Hunter NSW Daniel Repacholi ALP4.7
Blair Qld Shayne Neumann ALP5.23
Reid NSW Sally Sitou ALP5.24
Werriwa NSW Anne Stanley ALP5.3
Bruce Vic Julian Hill ALP5.4
Dobell NSW Emma McBride ALP5.61
Fairly safe
Shortland NSW Pat Conroy ALP6
Eden-Monaro NSW Kristy McBain ALP6.2
Macquarie NSW Susan Templeman ALP6.3
Aston Vic Mary Doyle ALP6.38
Dunkley Vic Jodie Belyea ALP6.8
Holt Vic Cassandra Fernando ALP7.12
Hawke Vic Sam Rae ALP7.63
Richmond NSW Justine Elliot ALP7.8
Corangamite Vic Libby Coker ALP7.8
Greenway NSW Michelle Rowland ALP8.1
Whitlam NSW Stephen Jones ALP8.4
Pearce NSW Tracey Roberts ALP8.8
Hindmarsh SA Mark Butler ALP8.95
Rankin Qld Jim Chalmers ALP9.09
Moreton Qld Graham Perrett ALP9.09
Solomon NT Luke Gosling ALP9.37
Swan WA Zaneta Mascarenhas ALP9.4
Isaacs Vic Mark Dreyfus ALP9.5
Macarthur NSW Mike Freelander ALP9.8
Safe
Cowan WA Anne Aly ALP10
Gorton Vic Brendan O'Connor ALP10
Hasluck WA Tania Lawrence ALP10.1
McMahon NSW Chris Bowen ALP10.5
Lilley Qld Anika Wells ALP10.54
Makin SA Tony Zappia ALP10.8
Gellibrand Vic Tim Watts ALP11.2
Oxley Qld Milton Dick ALP11.59
Hotham Vic Clare O'Neil ALP11.6
Adelaide SA Steve Georganas ALP11.91
Bendigo Vic Lisa Chesters ALP12
Barton NSW Linda Burney ALP12
Jagajaga Vic Kate Thwaites ALP12.2
Macnamara Vic Josh Burns ALP12.25
Calwell Vic Maria Vamvakinou ALP12.39
Corio Vic Richard Marles ALP12.5
Lalor Vic Joanne Ryan ALP12.82
Maribyrnong Vic Bill Shorten ALP12.9
Spence SA Matt Burnell ALP12.9
Bean ACT David Smith ALP12.95
Ballarat Vic Catherine King ALP12.97
Blaxland NSW Jason Clare ALP13.1
Burt WA Matt Keogh ALP13.4
Kingsford Smith NSW Matt Thistlethwaite ALP13.4
Chifley NSW Ed Husic ALP13.6
Franklin Tas Julie Collins ALP13.7
Perth WA Patrick Gorman ALP14.4
Cunningham NSW Alison Byrnes ALP15.1
Watson NSW Tony Burke ALP15.21
Scullin Vic Andrew Giles ALP15.3
Fenner 15.69 Andrew Leigh ALP15.69
Kingston SA Amanda Rishworth ALP16.35
Fraser Vic Daniel Mulino ALP16.6
Fremantle WA Josh Wilson ALP17
Brand WA Madeleine King ALP17.1
Newcastle NSW Sharon Claydon ALP17.9
Canberra ACT Alicia Payne ALP (12.2% Margin ALP vs. GRN)22.46
Sydney NSW Tanya Plibersek ALP (16.5% Margin ALP vs. GRN)25.57
Cooper Vic Ged Kearney ALP (8.2% Margin ALP vs. GRN)25.7
Wills Vic Peter Khalil ALP (4.6% Margin ALP vs. GRN)27.1
Grayndler NSW Anthony Albanese ALP (17.3% Margin ALP vs. GRN)28.85
Opposition seats (54)
Marginal
Deakin Vic Michael Sukkar LIB0
Menzies Vic Keith Wolahan LIB0.4
Sturt SA James Stevens LIB0.45
Moore WA Ian Goodenough (Disendorsed for this election)LIB0.9
Canning WA Andrew Hastie LIB1.2
Bass Tas Bridget Archer LIB1.43
Casey Vic Aaron Violi LIB1.48
Dickson Qld Peter Dutton LNP1.7
Banks NSW David Coleman LIB2.6
Longman Qld Terry Young LNP3.08
Bonner Qld Ross Vasta LNP3.41
Leichhardt Qld Warren Entsch LNP3.44
Hughes NSW Jenny Ware LIB3.6
Flynn Qld Colin Boyce LNP3.82
Forrest WA Nola Marino LIB4.2
Forde Qld Bert Van Manen LNP4.23
Petrie Qld Luke Howarth LNP4.44
Durack WA Melissa Price LIB4.6
Bowman Qld Henry Pike LNP5.51
Fairly safe
Lindsay NSW Melissa McIntosh LIB6.1
Flinders Vic Zoe McKenzie LIB6.2
Bradfield NSW Paul Fletcher LIB (2.5% Margin LIB vs IND.)6.55
Capricornia Qld Michelle Landry LNP6.59
O'Connor WA Rick Wilson LIB6.7
Hume NSW Angus Taylor LIB6.9
Berowra NSW Julian Leeser LIB7.5
Braddon Tas Gavin Pearce LIB8.03
La Trobe Vic Jason Wood LIB8.4
Fisher Qld Andrew Wallace LNP8.67
Fairfax Qld Ted O'Brien LNP8.97
Wannon Vic Dan Tehan LIB (3.7% Margin LIB vs IND.)9.07
McPherson Qld Karen Andrews LNP9.34
Cowper NSW Pat Conaghan NAT (2.32% Margin NAT vs IND.)9.47
Riverina NSW Michael McCormack NAT9.7
Safe
Grey SA Rowan Ramsey LIB10.07
Hinkler Qld Keith Pitt LNP10.07
Dawson Qld Andrew Willcox LNP10.42
Mitchell NSW Alex Hawke LIB10.5
Page NSW Kevin Hogan NAT10.74
Wright Qld Scott Buchholz LNP10.89
Moncrieff Qld Angie Bell LNP11.19
Wide Bay Qld Llew O'Brien LNP11.34
Cook NSW Simon Kennedy LIB11.7
Herbert Qld Phillip Thompson LNP11.77
Fadden Qld Cameron Caldwell LNP13.35
Lyne NSW David Gillespie NAT13.8
Groom Qld Garth Hamilton LNP (6.89% Margin LNP vs. IND.)14.17
New England NSW Barnaby Joyce NAT15.2
Farrer NSW Sussan Ley LIB16.35
Nicholls Vic Sam Birrell NAT (3.6% Margin NAT vs. IND.)17.15
Parkes NSW Mark Coulton NAT18.1
Mallee Vic Anne Webster NAT18.99
Gippsland Vic Darren Chester NAT20.57
Maranoa Qld David Littleproud LNP22.12
Crossbench seats (17)
Marginal
Fowler NSW Dai Le IND vs. ALP1.1
Curtin WA Kate Chaney IND vs. LIB1.26
Kooyong Vic Monique Ryan IND vs. LIB2.2
Ryan Qld Elizabeth Watson-Brown GRN vs. LNP2.65
Monash Vic Russell Broadbent LIB vs ALP (Last election)2.9
Mackellar NSW Sophie Scamps IND vs. LIB3.3
Goldstein Vic Zoe Daniel IND vs. LIB3.3
Brisbane Qld Stephen Bates GRN vs. LNP3.73
Fairly safe
Melbourne Vic Adam Bandt GRN vs. ALP6.5
Wentworth NSW Allegra Spender IND vs. LIB6.8
Indi Vic Helen Haines IND vs. LIB9.08
Warringah NSW Zali Steggall IND vs. LIB9.4
Calare NSW Andrew Gee NAT vs IND (Last election)9.68
Safe
Griffith Qld Max Chandler-Mather GRN vs. LNP10.46
Mayo SA Rebekha Sharkie CA vs LIB12.27
Kennedy Qld Bob Katter KAP vs LNP13.1
Very safe
Clark Tas Andrew Wilkie IND vs ALP20.82





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The following pendulum is known as the Mackerras pendulum, invented by psephologist Malcolm Mackerras. Designed for the outcome of the 2007 federal election, the pendulum works by lining up all of the seats held in Parliament, 83 Labor, 55 Liberal, 10 National, and 2 independent, according to the percentage point margin on a two candidate preferred basis, as elected in 2007. The two candidate 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. Swing is 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 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 following pendulum is known as the Mackerras pendulum, invented by psephologist Malcolm Mackerras. Designed for the outcome of the 2010 federal election, the pendulum works by lining up all of the seats held in Parliament, 72 Labor, 72 Coalition, 1 Nationals WA, 1 Green and 4 independent, 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. Swing is 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 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 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.

At the 2016 federal election of the 150 House of Representatives seats the Liberal/National Coalition won 76, a one-seat majority, Labor won 69 seats and crossbenchers won the remaining five. A redistribution in 2017/18 changed the representation entitlements. For the next election, the number of seats in the House will increase to 151, South Australia will lose a seat, Victoria and the Australian Capital Territory (ACT) will gain one seat each.

The following pendulum is known as the Mackerras pendulum, invented by psephologist Malcolm Mackerras. Based upon the outcome of the 2007 federal election and changes before the 2010 election, the pendulum works by lining up all of the seats held in Parliament, 83 Labor, 55 Liberal, 9 National, and 3 independent, according to the percentage point margin on a two party preferred basis.

The following is a Mackerras pendulum for the 2014 Victorian state election.

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.

The Coalition won the 2016 federal election with a one-seat majority 76 of 150 lower house seats. Labor holds 69 seats while crossbenchers hold the remaining five.

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.

The Australian Labor Party won the 2022 federal election, winning 77 of 151 seats in the House of Representatives. The Coalition holds 58 seats, and crossbenchers hold the remaining 16.

References

  1. ↑ "Divisional classifications". Tally Room. Australian Electoral Commission. 11 July 2019. Retrieved 3 November 2022.
  2. ↑ Green, Antony (2024-09-05). "2024 Federal Redistributions – Final Boundaries for Victoria Released". Antony Green's Election Blog. Retrieved 2024-11-26.
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