The following is a Mackerras pendulum prior to the Queensland state election, 2017 . [1]
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 of Representatives, which is composed of single-member electorates and which uses a preferential voting system such as a Condorcet method or IRV.
"Very safe" seats require a swing of more than 20 points to change, "safe" seats 10–20 points to change, "fairly safe" seats 6–10 points, and "marginal" seats less than 6 points.
The term swing refers to the extent of change in voter support, typically from one election or opinion poll to another, expressed as a positive or negative percentage point. For the Australian House of Representatives and the lower houses of the parliaments of all the states and territories except Tasmania and the ACT, Australia employs preferential voting in single-member constituencies. Under the full-preference instant-runoff voting system, in each seat the candidate with the lowest vote is eliminated and their preferences are distributed, which is repeated until only two candidates remain. While every seat has a two-candidate preferred (TCP) result, seats where the major parties have come first and second are commonly referred to as having a two-party-preferred (TPP) result. The concept of "swing" in Australian elections is not simply a function of the difference between the votes of the two leading candidates, as it is in Britain. To know the majority of any seat, and therefore the swing necessary for it to change hands, it is necessary to know the preferences of all the voters, regardless of their first preference votes. It is not uncommon in Australia for candidates who have comfortable leads on the first count to fail to win the seat, because "preference flows" go against them.
The following pendulum is known as the Mackerras Pendulum, invented by psephologist Malcolm Mackerras. Designed for the outcome of the 2007 federal election, 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 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'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.
The following pendulum is known as the Mackerras Pendulum, invented by psephologist Malcolm Mackerras. Designed for the outcome of the 2010 federal election, the pendulum works by lining up all of the seats held in Parliament, 72 Labor, 72 Coalition, 1 Nationals WA, 1 Green and 4 independent, according to the percentage point margin on a two candidate preferred basis. The two party 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'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.
The following is a Mackerras pendulum for the Victorian state election, 2006.
The following is a Mackerras Pendulum for theNew South Wales state election 2007.
The following pendulum is known as the Mackerras Pendulum, invented by psephologist Malcolm Mackerras. Designed for the outcome of the 2010 Victorian state election, the pendulum works by lining up all of the seats held in Parliament, according to the percentage point margin on a two candidate preferred basis. The two party 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 swings usually tend to cancel each other out. "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.
The following is a Mackerras pendulum for the Queensland state election, 2009.
The following is a pendulum based on the outcome of the 2010 federal election and changes since, including the redistributions of seats in South Australia and Victoria. It is a Mackerras Pendulum, invented by psephologist Malcolm Mackerras, which works by lining up all of the seats held in Parliament according to the percentage point margin on a two-candidate-preferred basis. The two-party 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. Swings are 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's (AEC) 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. The swings for South Australian and Victorian seats are notional, based on calculations by the AEC.
The following is a Mackerras pendulum for the Victorian state election, 2002.
The following is a Mackerras pendulum for the Queensland state election, 2012.
At the 2016 federal election of the 150 House of Representatives seats the Liberal/National Coalition won 76, a one-seat majority, Labor won 69 seats and crossbenchers won the remaining five. A redistribution in 2017/18 changed the representation entitlements. For the next election, the number of seats in the House will increase to 151, South Australia will lose a seat, Victoria and the Australian Capital Territory (ACT) will gain one seat each.
The following pendulum is known as the Mackerras Pendulum, invented by psephologist Malcolm Mackerras. Based upon the outcome of the 2007 federal election and changes before the 2010 election, the pendulum works by lining up all of the seats held in Parliament, 83 Labor, 55 Liberal, 9 National, and 3 independent, according to the percentage point margin on a two party preferred basis.
The following is a Mackerras pendulum for the upcoming Victorian state election, 2014.
The 2018 Victorian state election was held on Saturday, 24 November 2018 to elect the 59th Parliament of Victoria. All 88 seats in the Legislative Assembly and all 40 seats in the Legislative Council were up for election. The first-term incumbent Labor government, led by Premier Daniel Andrews, won a second four-year term, defeating the Liberal/National Coalition opposition, led by Opposition Leader Matthew Guy. Minor party the Greens led by Samantha Ratnam also contested the election.
The following is a Mackerras pendulum prior to the Queensland state election, 2015.
The following is a Mackerras pendulum for the Queensland state election, 2015.
The following is a Mackerras pendulum for the New South Wales state election, 2015.
This is a Mackerras pendulum for the 2016 Australian federal election.
The following is a Mackerras pendulum for the Queensland state election, 2017.
The following is a Mackerras pendulum for the New South Wales state election, 2019.