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 (80)MarginalHerbertQldPeter LindsayLIB0.10Eden-MonaroNSWGary NairnLIB0.18HinklerQldPaul NevilleNAT0.34MoretonQldGary HardgraveLIB0.57PetrieQldTeresa GambaroLIB0.75RichmondNSWLarry AnthonyNAT0.77AdelaideSATrish WorthLIB0.91LongmanQldMal BroughLIB0.92MakinSATrish DraperLIB0.94La TrobeVicBob CharlesLIB0.99McEwenVicFran BaileyLIB1.04ParramattaNSWRoss CameronLIB1.07HindmarshSAChris GallusLIB1.23LindsayNSWJackie KellyLIB1.28MayoSAAlexander DownerLIB1.74 v DEMDeakinVicPhil BarresiLIB1.93RobertsonNSWJim LloydLIB2.01DunkleyVicBruce BillsonLIB2.04KalgoorlieWABarry HaaseLIB2.10PageNSWIan CausleyNAT2.36BallaratVicMichael RonaldsonLIB2.77Wide BayQldWarren TrussNAT2.86BlairQldCameron ThompsonLIB3.40 v ONPFlindersVicPeter ReithLIB3.72GilmoreNSWJoanna GashLIB4.04LeichhardtQldWarren EntschLIB4.05MacquarieNSWKerry BartlettLIB4.10ParkesNSWTony LawlerNAT4.11AstonVicPeter NugentLIB4.24FairfaxQldAlex SomlyayLIB4.36DawsonQldDe-Anne KellyNAT4.42CorangamiteVicStewart McArthurLIB4.50CaseyVicMichael WooldridgeLIB4.87FordeQldKay ElsonLIB5.25PearceWAJudi MoylanLIB5.30MenziesVicKevin AndrewsLIB5.40HughesNSWDanna ValeLIB5.52MacarthurNSWJohn FaheyLIB5.63TangneyWADaryl WilliamsLIB5.90Fairly safeBennelongNSWJohn HowardLIB6.03MooreWAMal WasherLIB6.04WentworthNSWAndrew ThomsonLIB6.32CowperNSWGarry NehlNAT6.36ForrestWAGeoff ProsserLIB6.88SturtSAChristopher PyneLIB7.29WannonVicDavid HawkerLIB7.44BoothbySAAndrew SouthcottLIB7.45FaddenQldDavid JullLIB7.59GreySABarry WakelinLIB8.04HumeNSWAlby SchultzLIB8.06GoldsteinVicDavid KempLIB8.15McPhersonQldMargaret MayLIB8.34GippslandVicPeter McGauranNAT8.83CookNSWBruce BairdLIB8.94RyanQldJohn MooreLIB9.52HigginsVicPeter CostelloLIB9.62LyneNSWMark VaileNAT9.72SafeIndiVicLou LiebermanLIB10.11FisherQldPeter SlipperLIB11.00KennedyQldBob KatterNAT11.19KooyongVicPetro GeorgiouLIB11.39North SydneyNSWJoe HockeyLIB12.22MoncrieffQldKathy SullivanLIB12.83New EnglandNSWStuart St. ClairNAT12.93WarringahNSWTony AbbottLIB12.93GroomQldIan MacfarlaneLIB13.04CurtinWAJulie BishopLIB13.28BerowraNSWPhilip RuddockLIB13.52GwydirNSWJohn AndersonNAT13.58BarkerSAPatrick SeckerLIB13.74MaranoaQldBruce ScottNAT14.42FarrerNSWTim FischerNAT14.62O'ConnorWAWilson TuckeyLIB15.14RiverinaNSWKay HullNAT15.30MackellarNSWBronwyn BishopLIB15.64WakefieldSANeil AndrewLIB16.26MalleeVicJohn ForrestNAT19.37MitchellNSWAlan CadmanLIB19.85Very safeMurrayVicSharman StoneLIB22.06BradfieldNSWBrendan NelsonLIB23.20 Opposition seats (67)MarginalBassTasMichelle O'ByrneALP0.06DicksonQldCheryl KernotALP0.12KingstonSADavid CoxALP0.47Northern TerritoryNTWarren SnowdonALP0.57McMillanVicChristian ZahraALP0.57StirlingWAJann McFarlaneALP1.04PatersonNSWBob HorneALP1.22ChisholmVicAnna BurkeALP2.07GriffithQldKevin RuddALP2.43SwanWAKim WilkieALP2.70LilleyQldWayne SwanALP3.13BowmanQldCon SciaccaALP3.29DobellNSWMichael LeeALP3.35BendigoVicSteve GibbonsALP3.47CanningWAJane GerickALP3.52CowanWAGraham EdwardsALP3.56BraddonTasSid SidebottomALP4.33BrisbaneQldArch BevisALP4.59LoweNSWJohn MurphyALP4.63CapricorniaQldKirsten LivermoreALP5.29Melbourne PortsVicMichael DanbyALP5.83JagajagaVicJenny MacklinALP5.91Fairly safeIsaacsVicGreg WiltonALP6.40FranklinTasHarry QuickALP6.60BruceVicAlan GriffinALP6.72BankNSWDaryl MelhamALP7.11BurkeVicNeil O'KeefeALP7.61OxleyQldBernie RipollALP8.20RankinQldCraig EmersonALP8.69BartonNSWRobert McClellandALP9.76GreenwayNSWFrank MossfieldALP9.94SafeFremantleWACarmen LawrenceALP10.02CanberraACTAnnette EllisALP10.06LyonsTasDick AdamsALP10.61CorioVicGavan O'ConnorALP11.36BrandWAKim BeazleyALP12.29WerriwaNSWMark LathamALP12.67ShortlandNSWJill HallALP12.81CharltonNSWKelly HoareALP12.97PerthWAStephen SmithALP13.28Kingsford SmithNSWLaurie BreretonALP13.40HothamVicSimon CreanALP13.56DenisonTasDuncan KerrALP14.51BonythonSAMartyn EvansALP14.53HunterNSWJoel FitzgibbonALP14.69FraserACTBob McMullanALP14.86HoltVicAnthony ByrneALP15.11Port AdelaideSARod SawfordALP16.10SydneyNSWTanya PlibersekALP16.89NewcastleNSWAllan MorrisALP17.33 v GRNWatsonNSWLeo McLeayALP17.47CunninghamNSWStephen MartinALP18.20CalwellVicAndrew TheophanousALP18.98ProspectNSWJanice CrosioALP19.71LalorVicJulia GillardALP19.82Very safeChifleyNSWRoger PriceALP20.89WillsVicKelvin ThomsonALP20.96ReidNSWLaurie FergusonALP21.64MelbourneVicLindsay TannerALP21.80ScullinVicHarry JenkinsALP21.84BlaxlandNSWMichael HattonALP22.06MaribyrnongVicBob SercombeALP22.06GrayndlerNSWAnthony AlbaneseALP22.32ThrosbyNSWColin HollisALP22.46GellibrandVicNicola RoxonALP25.91FowlerNSWJulia IrwinALP26.33BatmanVicMartin FergusonALP26.43Crossbench seats (1)CalareNSWPeter AndrenIND22.31 v ALP
References