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.
Government seats (82)MarginalHinklerQldPaul NevilleNAT0.04SolomonNTDave TollnerCLP0.09FarrerNSWSussan LeyLIB0.14 v NATAdelaideSATrish WorthLIB0.22DobellNSWKen TicehurstLIB0.38CanningWADon RandallLIB0.38ParramattaNSWRoss CameronLIB1.15McEwenVicFran BaileyLIB1.20PatersonNSWBob BaldwinLIB1.42HerbertQldPeter LindsayLIB1.62RichmondNSWLarry AnthonyNAT1.68Eden-MonaroNSWGary NairnLIB1.69DeakinVicPhil BarresiLIB1.74HindmarshSAChris GallusLIB1.86LongmanQldMal BroughLIB2.72PageNSWIan CausleyNAT2.77PetrieQldTeresa GambaroLIB3.42La TrobeVicBob CharlesLIB3.67MakinSATrish DraperLIB3.76MoretonQldGary HardgraveLIB4.21KalgoorlieWABarry HaaseLIB4.34CowperNSWLuke HartsuykerNAT4.73DunkleyVicBruce BillsonLIB5.42LindsayNSWJackie KellyLIB5.47CorangamiteVicStewart McArthurLIB5.67WarringahNSWTony AbbottLIB5.67 v INDDicksonQldPeter DuttonLIB5.97Fairly safeMooreWAMal WasherLIB6.04AstonVicChris PearceLIB6.17LeichhardtQldWarren EntschLIB6.39PearceWAJudi MoylanLIB6.87RobertsonNSWJim LloydLIB6.98CaseyVicTony SmithLIB7.16BoothbySAAndrew SouthcottLIB7.35FordeQldKay ElsonLIB7.38ForrestWAGeoff ProsserLIB7.61FlindersVicGreg HuntLIB7.62BennelongNSWJohn HowardLIB7.70WentworthNSWPeter KingLIB7.86TangneyWADaryl WilliamsLIB7.97DawsonQldDe-Anne KellyNAT7.99GippslandVicPeter McGauranNAT8.02SturtSAChristopher PyneLIB8.18HigginsVicPeter CostelloLIB8.39BlairQldCameron ThompsonLIB8.50RyanQldMichael JohnsonLIB8.62MacquarieNSWKerry BartlettLIB8.67ParkesNSWJohn CobbNAT8.74MenziesVicKevin AndrewsLIB8.94FairfaxQldAlex SomlyayLIB9.21GoldsteinVicDavid KempLIB9.48WannonVicDavid HawkerLIB9.58HumeNSWAlby SchultzLIB9.79MacarthurNSWPat FarmerLIB9.96SafeHughesNSWDanna ValeLIB10.41GreySABarry WakelinLIB10.56Wide BayQldWarren TrussNAT10.73KooyongVicPetro GeorgiouLIB10.94IndiVicSophie PanopoulosLIB11.19LyneNSWMark VaileNAT11.24FisherQldPeter SlipperLIB12.06FaddenQldDavid JullLIB12.29McPhersonQldMargaret MayLIB12.55MayoSAAlexander DownerLIB12.87North SydneyNSWJoe HockeyLIB13.21CurtinWAJulie BishopLIB13.91CookNSWBruce BairdLIB14.00WakefieldSANeil AndrewLIB14.57GilmoreNSWJoanna GashLIB14.63GwydirNSWJohn AndersonNAT14.88GroomQldIan MacfarlaneLIB15.09MoncrieffQldSteven CioboLIB15.42BerowraNSWPhilip RuddockLIB15.65BarkerSAPatrick SeckerLIB15.69MaranoaQldBruce ScottNAT16.01MackellarNSWBronwyn BishopLIB16.87O'ConnorWAWilson TuckeyLIB19.09MalleeVicJohn ForrestNAT19.93Very safeBradfieldNSWBrendan NelsonLIB21.16MitchellNSWAlan CadmanLIB21.32MurrayVicSharman StoneLIB23.93RiverinaNSWKay HullNAT29.88 Opposition seats (65)MarginalBowmanQldCon SciaccaALP1.42StirlingWAJann McFarlaneALP1.58HasluckWASharryn JacksonALP1.78SwanWAKim WilkieALP2.04BassTasMichelle O'ByrneALP2.06KingstonSADavid CoxALP2.42McMillanVicChristian ZahraALP2.46BallaratVicCatherine KingALP2.73ChisholmVicAnna BurkeALP2.77IsaacsVicAnn CorcoranALP2.81BanksNSWDaryl MelhamALP2.88GreenwayNSWFrank MossfieldALP3.11BrisbaneQldArch BevisALP3.13BendigoVicSteve GibbonsALP3.57LoweNSWJohn MurphyALP3.81LilleyQldWayne SwanALP4.83LingiariNTWarren SnowdonALP5.29CowanWAGraham EdwardsALP5.51BurkeVicBrendan O'ConnorALP5.51BruceVicAlan GriffinALP5.55JagajagaVicJenny MacklinALP5.64GriffithQldKevin RuddALP5.66Melbourne PortsVicMichael DanbyALP5.69BraddonTasSid SidebottomALP5.96Fairly safeBartonNSWRobert McClellandALP6.02CharltonNSWKelly HoareALP6.66RankinQldCraig EmersonALP6.68CapricorniaQldKirsten LivermoreALP6.86NewcastleNSWSharon GriersonALP6.91FranklinTasHarry QuickALP8.04OxleyQldBernie RipollALP8.14LyonsTasDick AdamsALP8.17WerriwaNSWMark LathamALP8.49CorioVicGavan O'ConnorALP8.70ShortlandNSWJill HallALP8.78Kingsford SmithNSWLaurie BreretonALP8.90CanberraACTAnnette EllisALP9.44SafeBrandWAKim BeazleyALP10.05BonythonSAMartyn EvansALP10.42CunninghamNSWStephen MartinALP10.65FremantleWACarmen LawrenceALP10.72HunterNSWJoel FitzgibbonALP10.86HothamVicSimon CreanALP11.01PerthWAStephen SmithALP11.21ProspectNSWJanice CrosioALP12.81FraserACTBob McMullanALP12.96HoltVicAnthony ByrneALP13.32DenisonTasDuncan KerrALP14.26Port AdelaideSARod SawfordALP14.65SydneyNSWTanya PlibersekALP15.04ThrosbyNSWJennie GeorgeALP15.10BlaxlandNSWMichael HattonALP15.21ChifleyNSWRoger PriceALP15.29LalorVicJulia GillardALP15.63ReidNSWLaurie FergusonALP16.87WatsonNSWLeo McLeayALP17.31MaribyrnongVicBob SercombeALP17.38CalwellVicMaria VamvakinouALP17.73ScullinVicHarry JenkinsALP19.17WillsVicKelvin ThomsonALP19.42Very safeMelbourneVicLindsay TannerALP20.09GrayndlerNSWAnthony AlbaneseALP21.29FowlerNSWJulia IrwinALP21.50GellibrandVicNicola RoxonALP21.78BatmanVicMartin FergusonALP25.08Crossbench seats (3)New EnglandNSWTony WindsorIND8.30 v NATKennedyQldBob KatterIND19.73 v ALPCalareNSWPeter AndrenIND25.04 v NAT
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