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 (87)MarginalKingstonSAKym RichardsonLIB0.07BonnerQldRoss VastaLIB0.51GreenwayNSWLouise MarkusLIB0.58WakefieldSADavid FawcettLIB0.67MakinSATrish DraperLIB0.93BraddonTasMark BakerLIB1.13HasluckWAStuart HenryLIB1.82StirlingWAMichael KeenanLIB2.04Eden-MonaroNSWGary NairnLIB2.14BassTasMichael FergusonLIB2.63SolomonNTDave TollnerCLP2.81MoretonQldGary HardgraveLIB4.17PageNSWIan CausleyNAT4.23BennelongNSWJohn HowardLIB4.33HinklerQldPaul NevilleNAT4.81DeakinVicPhil BarresiLIB4.97McMillanVicRussell BroadbentLIB4.99LindsayNSWJackie KellyLIB5.26CorangamiteVicStewart McArthurLIB5.32BoothbySAAndrew SouthcottLIB5.37WentworthNSWMalcolm TurnbullLIB5.48La TrobeVicJason WoodLIB5.83DobellNSWKen TicehurstLIB5.90Fairly safeHerbertQldPeter LindsayLIB6.20KalgoorlieWABarry HaaseLIB6.30McEwenVicFran BaileyLIB6.42CowperNSWLuke HartsuykerNAT6.45SturtSAChristopher PyneLIB6.80RobertsonNSWJim LloydLIB6.81PatersonNSWBob BaldwinLIB6.97LongmanQldMal BroughLIB7.66GippslandVicPeter McGauranNAT7.70DicksonQldPeter DuttonLIB7.83PetrieQldTeresa GambaroLIB7.92HigginsVicPeter CostelloLIB8.76MacquarieNSWKerry BartlettLIB8.92BowmanQldAndrew LamingLIB9.12DunkleyVicBruce BillsonLIB9.38MacarthurNSWPat FarmerLIB9.51CanningWADon RandallLIB9.54KooyongVicPetro GeorgiouLIB9.58LeichhardtQldWarren EntschLIB10.00SafeNorth SydneyNSWJoe HockeyLIB10.03GoldsteinVicAndrew RobbLIB10.03GilmoreNSWJoanna GashLIB10.08DawsonQldDe-Anne KellyNAT10.38RyanQldMichael JohnsonLIB10.42ForrestWAGeoff ProsserLIB10.45WarringahNSWTony AbbottLIB10.48MenziesVicKevin AndrewsLIB10.67FairfaxQldAlex SomlyayLIB10.83MooreWAMal WasherLIB10.83HughesNSWDanna ValeLIB11.04FlindersVicGreg HuntLIB11.11BlairQldCameron ThompsonLIB11.21CaseyVicTony SmithLIB11.35TangneyWADennis JensenLIB11.75MayoSAAlexander DownerLIB11.81 v INDBerowraNSWPhilip RuddockLIB12.16WannonVicDavid HawkerLIB12.37Wide BayQldWarren TrussNAT12.89PearceWAJudi MoylanLIB12.94FisherQldPeter SlipperLIB12.98FordeQldKay ElsonLIB12.98LyneNSWMark VaileNAT13.03AstonVicChris PearceLIB13.15CookNSWBruce BairdLIB13.82GreySABarry WakelinLIB13.82McPhersonQldMargaret MayLIB13.89HumeNSWAlby SchultzLIB14.13ParkesNSWJohn CobbNAT14.40CurtinWAJulie BishopLIB14.62FaddenQldDavid JullLIB15.28MackellarNSWBronwyn BishopLIB15.75IndiVicSophie PanopoulosLIB16.29GwydirNSWJohn AndersonNAT18.39BradfieldNSWBrendan NelsonLIB18.51GroomQldIan MacfarlaneLIB18.95FarrerNSWSussan LeyLIB19.82BarkerSAPatrick SeckerLIB19.88Very safeMoncrieffQldSteven CioboLIB20.14O'ConnorWAWilson TuckeyLIB20.39RiverinaNSWKay HullNAT20.66MitchellNSWAlan CadmanLIB20.68MaranoaQldBruce ScottNAT20.93MurrayVicSharman StoneLIB24.08MalleeVicJohn ForrestNAT24.75 Opposition seats (60)MarginalHindmarshSASteve GeorganasALP0.06SwanWAKim WilkieALP0.08RichmondNSWJustine ElliotALP0.19ParramattaNSWJulie OwensALP0.77CowanWAGraham EdwardsALP0.78BendigoVicSteve GibbonsALP0.96BanksNSWDaryl MelhamALP1.06AdelaideSAKate EllisALP1.33IsaacsVicAnn CorcoranALP1.48HoltVicAnthony ByrneALP1.51BallaratVicCatherine KingALP2.23ChisholmVicAnna BurkeALP2.65RankinQldCraig EmersonALP3.23LoweNSWJohn MurphyALP3.30BruceVicAlan GriffinALP3.48LyonsTasDick AdamsALP3.68Melbourne PortsVicMichael DanbyALP3.74BrisbaneQldArch BevisALP3.90JagajagaVicJenny MacklinALP4.40BrandWAKim BeazleyALP4.65CapricorniaQldKirsten LivermoreALP5.14LilleyQldWayne SwanALP5.27CorioVicGavan O'ConnorALP5.64Fairly safePerthWAStephen SmithALP6.73ProspectNSWChris BowenALP7.12HothamVicSimon CreanALP7.40BartonNSWRobert McClellandALP7.54FranklinTasHarry QuickALP7.59LingiariNTWarren SnowdonALP7.66FremantleWACarmen LawrenceALP7.76CharltonNSWKelly HoareALP7.92CalwellVicMaria VamvakinouALP8.19GriffithQldKevin RuddALP8.63LalorVicJulia GillardALP8.79Kingsford SmithNSWPeter GarrettALP9.01WerriwaNSWMark LathamALP9.31MaribyrnongVicBob SercombeALP9.47ShortlandNSWJill HallALP9.49CanberraACTAnnette EllisALP9.62OxleyQldBernie RipollALP9.72NewcastleNSWSharon GriersonALP9.98SafeCunninghamNSWSharon BirdALP11.46ReidNSWLaurie FergusonALP12.77BlaxlandNSWMichael HattonALP12.87Port AdelaideSARod SawfordALP12.91ChifleyNSWRoger PriceALP12.98DenisonTasDuncan KerrALP13.29FraserACTBob McMullanALP13.33HunterNSWJoel FitzgibbonALP13.75ScullinVicHarry JenkinsALP14.79GortonVicBrendan O'ConnorALP14.90GellibrandVicNicola RoxonALP14.95ThrosbyNSWJennie GeorgeALP15.00WatsonNSWTony BurkeALP15.14SydneyNSWTanya PlibersekALP16.42WillsVicKelvin ThomsonALP16.90Very safeMelbourneVicLindsay TannerALP21.14BatmanVicMartin FergusonALP21.32FowlerNSWJulia IrwinALP21.36GrayndlerNSWAnthony AlbaneseALP22.60Crossbench seats (3)KennedyQldBob KatterIND18.88 v ALPNew EnglandNSWTony WindsorIND21.00 v NATCalareNSWPeter AndrenIND21.24 v LIB
References