The following pendulum is known as the

Mackerras pendulum 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 ...

, invented by psephologist

Malcolm Mackerras Malcolm Hugh Mackerras AO (born 26 August 1939) is an Australian psephologist and commentator and lecturer on Australian and American politics. Education and works Malcolm Mackerras was born at Turramurra in Sydney in August 1939. He is a brot ...

. Designed for the outcome of the

2007 federal election This electoral calendar 2007 lists the national/federal direct elections held in 2007 in the de jure and de facto sovereign states and their dependent territories. Referendums are included, although they are not elections. By-elections are not i ...

, the pendulum works by lining up all of the seats held in Parliament, 83 Labor, 55 Liberal, 10 National, and 2 independent, according to the

percentage point A percentage point or percent point is the unit (measurement), unit for the Difference (mathematics), arithmetic difference between two percentages. For example, moving up from 40 percent to 44 percent is an increase of 4 percentage points, but a ...

margin on a two candidate preferred basis, as elected in 2007. The two candidate result is also known as the swing required for the seat to change hands. Given a uniform swing to the opposition or government parties in an election, the number of seats that change hands can be predicted. Swing is never uniform, but in practice variations of swing among the Australian states usually tend to cancel each other out. Seats are arranged in safeness categories according to the

Australian Electoral Commission The Australian Electoral Commission (AEC) is the independent federal agency in charge of organising, conducting and supervising federal Australian elections, by-elections and referendums. Responsibilities The AEC's main responsibility is to ...

's classification of safeness. "Safe" seats require a swing of over 10 per cent to change, "fairly safe" seats require a swing of between 6 and 10 per cent, while "marginal" seats require a swing of less than 6 per cent.Electoral matrix: 2004 federal election

References

{{2007 Australian federal election 2007 elections in Australia Pendulums for Australian federal elections