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 (74)MarginalWilmotTasMax BurrLIB0.1KingstonSAGrant ChapmanLIB0.2BartonNSWJim BradfieldLIB0.4RiverinaNSWNoel HicksNCP0.5PhillipNSWJack BirneyLIB0.6HerbertQldGordon DeanLIB0.9PerthWARoss McLeanLIB1.0LoweNSWWilliam McMahonLIB1.1LeichhardtQldDavid ThomsonNCP1.1BowmanQldDavid JullLIB1.2Northern TerritoryNTGrant TamblingCLP1.2BendigoVicJohn BourchierLIB1.3CalareNSWSandy MackenzieNCP1.5FaddenQldDon CameronLIB1.5CanningWAMel BungeyLIB1.8CaseyVicPeter FalconerLIB1.9StirlingWAIan VinerLIB2.0ChisholmVicGraham HarrisLIB2.2DawsonQldRay BraithwaiteNCP2.2DeakinVicAlan JarmanLIB2.3DenisonTasMichael HodgmanLIB2.4FranklinTasBruce GoodluckLIB2.7Eden-MonaroNSWMurray SainsburyLIB2.8MooreWAJohn HydeLIB2.8MacarthurNSWMichael BaumeLIB3.2PetrieQldJohn HodgesLIB3.4McPhersonQldEric RobinsonLIB3.6Diamond ValleyVicNeil BrownLIB3.7SturtSAIan WilsonLIB4.0BassTasKevin NewmanLIB4.3Wide BayQldClarrie MillarNCP4.4FlindersVicPhillip LynchLIB4.6MoretonQldJames KillenLIB4.6TangneyWAPeter ShackLIB4.6CookNSWDon DobieLIB5.1BraddonTasRay GroomLIB5.1BruceVicBilly SneddenLIB5.4Fairly safeBalaclavaVicIan MacpheeLIB6.1CowperNSWIan RobinsonNCP6.5New EnglandNSWIan SinclairNCP6.5HumeNSWStephen LusherNCP6.9BarkerSAJames PorterLIB7.5PatersonNSWFrank O'KeefeNCP7.7BennelongNSWJohn HowardLIB8.4DundasNSWPhilip RuddockLIB8.4LyneNSWBruce CowanNCP8.9FisherQldEvan AdermannNCP8.9ForrestWAPeter DrummondLIB9.8SafeRichmondNSWDoug AnthonyNCP10.3GwydirNSWRalph HuntNCP10.4RyanQldJohn MooreLIB10.4HigginsVicRoger ShiptonLIB10.7KooyongVicAndrew PeacockLIB11.1WannonVicMalcolm FraserLIB11.2FarrerNSWWal FifeLIB11.8GippslandVicPeter NixonNCP11.9CurtinWAVictor GarlandLIB12.3IndiVicEwen CameronLIB12.4O'ConnorWAWilson TuckeyLIB12.5 v NCPBoothbySAJohn McLeay Jr.LIB12.6KennedyQldBob Katter Sr.NCP12.7CorangamiteVicTony StreetLIB12.8WentworthNSWBob EllicottLIB13.0MackellarNSWJim CarltonLIB13.5North SydneyNSWJohn SpenderLIB14.5BerowraNSWHarry EdwardLIB15.0MitchellNSWAlan CadmanLIB15.6Darling DownsQldTom McVeighNCP15.8WakefieldSAGeoffrey GilesLIB16.2MaranoaQldIan CameronNCP17.1WarringahNSWMichael MacKellarLIB17.4MurrayVicBruce LloydNCP17.5Very safeMalleeVicPeter FisherNCP20.8BradfieldNSWDavid ConnollyLIB28.1 Opposition seats (51)MarginalKalgoorlieWAGraeme CampbellALP0.6BallaratVicJohn MildrenALP0.7LilleyQldElaine DarlingALP0.8McMillanVicBarry CunninghamALP1.4IsaacsVicDavid CharlesALP1.8BrisbaneQldManfred CrossALP1.8La TrobeVicPeter MiltonALP2.3MacquarieNSWRoss FreeALP2.8HentyVicJoan ChildALP2.8GreySALaurie WallisALP3.4HawkerSARalph JacobiALP3.8HothamVicLewis KentALP4.0CapricorniaQldDoug EveringhamALP4.3CanberraACTRos KellyALP5.7Fairly safeSt GeorgeNSWBill MorrisonALP6.1HindmarshSAJohn ScottALP6.2HoltVicMichael DuffyALP6.9SwanWAKim BeazleyALP7.6RobertsonNSWBarry CohenALP8.1AdelaideSAChris HurfordALP8.5BanksNSWJohn MountfordALP8.8BurkeVicAndrew TheophanousALP8.8CorioVicGordon ScholesALP9.8SafeParramattaNSWJohn BrownALP10.2BatmanVicBrian HoweALP10.7MaribyrnongVicMoss CassALP10.7ProspectNSWDick KlugmanALP11.2HughesNSWLes JohnsonALP12.1Melbourne PortsVicClyde HoldingALP12.3BonythonSANeal BlewittALP12.4FraserACTKen FryALP12.5GriffithQldBen HumphreysALP12.5FremantleWAJohn DawkinsALP13.1GrayndlerNSWLeo McLeayALP13.5NewcastleNSWCharles JonesALP13.8CunninghamNSWStewart WestALP15.1ReidNSWTom UrenALP15.5WerriwaNSWJohn KerinALP16.6BlaxlandNSWPaul KeatingALP17.2MelbourneVicTed InnesALP18.1OxleyQldBill HaydenALP18.8Port AdelaideSAMick YoungALP18.8ShortlandNSWPeter MorrisALP19.3WillsVicBob HawkeALP19.9Very safeChifleyNSWJohn ArmitageALP20.1ScullinVicHarry Jenkins, Sr.ALP20.6HunterNSWBob BrownALP21.3Kingsford SmithNSWLionel BowenALP21.5LalorVicBarry JonesALP21.9GellibrandVicRalph WillisALP23.4SydneyNSWLes McMahonALP23.8
References