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'."
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. 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.
Government (78 seats)MarginalGilmoreNSWFiona PhillipsALP0.2MenziesVicKeith Wolahan (LIB)ALP0.4LyonsTasBrian MitchellALP0.9LingiariNTMarion ScrymgourALP1.7RobertsonNSWGordon ReidALP2.2PatersonNSWMeryl SwansonALP2.6TangneyWASam LimALP2.8BoothbySALouise Miller-FrostALP3.3ChisholmVicCarina GarlandALP3.3BullwinkelWANew divisionALP3.3AstonVicMary DoyleALP (b/e)3.6ParramattaNSWAndrew CharltonALP3.7McEwenVicRob MitchellALP3.8WillsVicPeter KhalilALP v GRN4.6HunterNSWDaniel RepacholiALP4.8ReidNSWSally SitouALP5.2BlairQldShayne NeumannALP5.2BruceVicJulian HillALP5.3WerriwaNSWAnne StanleyALP5.3Fairly safeShortlandNSWPat ConroyALP6.0Eden-MonaroNSWKristy McBainALP6.1MacquarieNSWSusan TemplemanALP6.3DobellNSWEmma McBrideALP6.6DunkleyVicJodie BelyeaALP6.8HoltVicCassandra FernandoALP7.1HawkeVicSam RaeALP7.6CooperVicGed KearneyALP v GRN7.8CorangamiteVicLibby CokerALP7.8GreenwayNSWMichelle RowlandALP7.9RichmondNSWJustine ElliotALP8.2WhitlamNSWStephen JonesALP8.3SolomonNTLuke GoslingALP8.4PearceWATracey RobertsALP8.8HindmarshSAMark ButlerALP8.9RankinQldJim ChalmersALP9.1MoretonQldGraham PerrettALP9.1SwanWAZaneta MascarenhasALP9.4IsaacsVicMark DreyfusALP9.5MacarthurNSWMike FreelanderALP9.8CowanWAAnne AlyALP9.9SafeGortonVicBrendan O'ConnorALP10.0HasluckWATania LawrenceALP10.0McMahonNSWChris BowenALP10.5LilleyQldAnika WellsALP10.5MakinSATony ZappiaALP10.8BendigoVicLisa ChestersALP11.2GellibrandVicTim WattsALP11.2HothamVicClare O'NeilALP11.6OxleyQldMilton DickALP11.6AdelaideSASteve GeorganasALP11.9BartonNSWLinda BurneyALP12.0MacnamaraVicJosh BurnsALP12.2JagajagaVicKate ThwaitesALP12.2CanberraACTAlicia PayneALP v GRN12.2CalwellVicMaria VamvakinouALP12.4CorioVicRichard MarlesALP12.5LalorVicJoanne RyanALP12.8SpenceSAMatt BurnellALP12.9BeanACTDavid SmithALP12.9BallaratVicCatherine KingALP13.0MaribyrnongVicBill ShortenALP13.0BlaxlandNSWJason ClareALP13.0BurtWAMatt KeoghALP13.3Kingsford SmithNSWMatt ThistlethwaiteALP13.3ChifleyNSWEd HusicALP13.6FranklinTasJulie CollinsALP13.7PerthWAPatrick GormanALP14.4CunninghamNSWAlison ByrnesALP15.1WatsonNSWTony BurkeALP15.2ScullinVicAndrew GilesALP15.4FennerACTAndrew LeighALP15.7KingstonSAAmanda RishworthALP16.4SydneyNSWTanya PlibersekALP v GRN16.5FraserVicDaniel MulinoALP16.6FremantleWAJosh WilsonALP16.9BrandWAMadeleine KingALP17.1GrayndlerNSWAnthony AlbaneseALP v GRN17.3NewcastleNSWSharon ClaydonALP17.9
Opposition (57 seats) MarginalDeakinVicMichael SukkarLIB0.02BennelongNSWJerome Laxale (ALP)LIB0.04SturtSAJames StevensLIB0.5MooreWAIan Goodenough (IND)LIB0.9CanningWAAndrew HastieLIB1.2BassTasBridget ArcherLIB1.4CaseyVicAaron VioliLIB1.4DicksonQldPeter DuttonLNP1.7CowperNSWPat ConaghanNAT v IND2.4BradfieldNSWPaul FletcherLIB v IND2.5BanksNSWDavid ColemanLIB2.6MonashVicRussell Broadbent (IND)LIB2.9LongmanQldTerry YoungLNP3.1BonnerQldRoss VastaLNP3.4LeichhardtQldWarren EntschLNP3.4NichollsVicSam BirrellNAT v IND3.4HughesNSWJenny WareLIB3.5FlynnQldColin BoyceLNP3.8WannonVicDan TehanLIB v IND3.8ForrestWANola MarinoLIB4.2FordeQldBert Van ManenLNP4.2PetrieQldLuke HowarthLNP4.4DurackWAMelissa PriceLIB4.7BowmanQldHenry PikeLNP5.5Fairly safeLindsayNSWMelissa McIntoshLIB6.1FlindersVicZoe McKenzieLIB6.2CapricorniaQldMichelle LandryLNP6.6O'ConnorWARick WilsonLIB6.7HumeNSWAngus TaylorLIB6.9GroomQldGarth HamiltonLNP v IND6.9BerowraNSWJulian LeeserLIB7.6BraddonTasGavin PearceLIB8.0La TrobeVicJason WoodLIB8.4FisherQldAndrew WallaceLNP8.7FairfaxQldTed O'BrienLNP9.0McPhersonQldKaren AndrewsLNP9.3RiverinaNSWMichael McCormackNAT9.7CalareNSWAndrew Gee (IND)NAT v IND9.7SafeGreySARowan RamseyLIB10.1HinklerQldKeith PittLNP10.1DawsonQldAndrew WillcoxLNP10.4MitchellNSWAlex HawkeLIB10.5FaddenQldCameron CaldwellLNP10.6PageNSWKevin HoganNAT10.7WrightQldScott BuchholzLNP10.9MoncrieffQldAngie BellLNP11.2Wide BayQldLlew O'BrienLNP11.3CookNSWSimon KennedyLIB11.6HerbertQldPhillip ThompsonLNP11.8LyneNSWDavid GillespieNAT13.8New EnglandNSWBarnaby JoyceNAT15.2FarrerNSWSussan LeyLIB16.3BarkerSATony PasinLIB16.6ParkesNSWMark CoultonNAT18.2MalleeVicAnne WebsterNAT19.0GippslandVicDarren ChesterNAT20.6MaranoaQldDavid LittleproudLNP22.1Crossbench (15 seats)FowlerNSWDai LeIND v ALP1.1CurtinWAKate ChaneyIND v LIB1.3KooyongVicMonique RyanIND v LIB2.2RyanQldElizabeth Watson-BrownGRN v LNP2.6GoldsteinVicZoe DanielIND v LIB3.3MackellarNSWSophie ScampsIND v LIB3.3BrisbaneQldStephen BatesGRN v LNP3.7MelbourneVicAdam BandtGRN v ALP6.5WentworthNSWAllegra SpenderIND v LIB6.8IndiVicHelen HainesIND v LIB8.9WarringahNSWZali SteggallIND v LIB9.4GriffithQldMax Chandler-MatherGRN v LNP10.5MayoSARebekha SharkieCA v LIB12.3KennedyQldBob KatterKAP v LNP13.1ClarkTasAndrew WilkieIND v ALP20.8
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