Two-party-preferred vote

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Instant-runoff voting method. TPP/TCP vote is calculated when two candidates remain. IRV counting flowchart.svg
Instant-runoff voting method. TPP/TCP vote is calculated when two candidates remain.

In Australian politics, the two-party-preferred vote (TPP or 2PP) is the result of an election or opinion poll after preferences have been distributed to the highest two candidates, who in some cases can be independents. For the purposes of TPP, the Liberal/National Coalition is usually considered a single party, with Labor being the other major party. Typically the TPP is expressed as the percentages of votes attracted by each of the two major parties, e.g. "Coalition 50%, Labor 50%", where the values include both primary votes and preferences. The TPP is an indicator of how much swing has been attained/is required to change the result, taking into consideration preferences, which may have a significant effect on the result.

Contents

The TPP assumes a two-party system, i.e. that after distribution of votes from less successful candidates, the two remaining candidates will be from the two major parties. However, in some electorates this is not the case. The two-candidate-preferred vote (TCP) is the result after preferences have been distributed, using instant-runoff voting, to the final two candidates, regardless of which party the candidates represent. For electorates where the two candidates are from the major parties, the TCP is also the TPP. For electorates where these two candidates are not both from the major parties, preferences are notionally distributed to the two major parties to determine the TPP. In this case the TPP differs from the TCP, and is not informative. TPP results above seat-level, such as a national or statewide TPP, are also informative only and have no direct effect on the election outcome.

The full allocation of preferences under instant-runoff voting is used in the lower houses of the Federal, Queensland, Victorian, Western Australian, South Australian, and Northern Territory parliaments, as well as the upper house of Tasmania. The New South Wales lower house uses optional-preference instant runoff voting – with some votes giving limited or no preferences, TPP/TCP is not as meaningful. TPP/TCP does not occur in the Tasmanian lower house or the Australian Capital Territory due to a different system altogether, the Hare–Clark proportional voting system. Aside from Tasmania, TPP/TCP is not used in any other upper houses in Australia, with most using the group ticket single transferable proportional voting system. [1]

History

Australia originally used first-past-the-post voting as used by the House of Commons of the United Kingdom. Federal election full-preference instant-runoff voting was introduced by the government of the day after the 1918 Swan by-election, and has been in use ever since. In that by-election, candidates from the Australian Labor Party, the Nationalist Party government (predecessor to the United Australia Party and Liberal Party of Australia), and the emerging National Party of Australia (then Country Party) all received around a third of the vote, however, as Labor had a plurality of three percent, it won the seat. The new system allowed the two non-Labor parties to compete against one another in many seats without risking losing the seat altogether.

The Coalition now includes four parties: the Liberal Party of Australia except Queensland and the Northern Territory, the National Party of Australia in New South Wales and Victoria, the Liberal National Party of Queensland, and the Country Liberal Party in the Northern Territory. It is increasingly uncommon for seats to be contested by more than one Coalition candidate. For example, in the 2010 federal election, only three seats were contested by more than one Coalition candidate. With the popularity of parties such as the Greens and One Nation, preference flows are very significant for all parties in Australia.

Not distributing preferences was historically common in seats where a candidate received over 50 percent of the primary vote. Federal seat and national TPP results have only been produced as far back as 1937, though it was not uncommon in the next few decades for major parties at federal elections to not field a candidate in a few "safe" seats, but since 1972, all seats at federal elections have been contested by the major parties. Full preference distributions have occurred in all seats since 1983. [2]

South Australian state elections have boundaries strategically redrawn before each election with a fairness aim based on the prior election TPP vote, the only state to do so. The culmination of the historical state lower house seat malapportionment known as the Playmander eventually saw it legislated after 1989 that the Electoral Commission of South Australia redraw boundaries after each election with the objective of the party that receives over 50 percent of the TPP vote at each forthcoming election forms government. Nationally in 1983/84, minor gerrymandering by incumbent federal governments was legislated against with the formation of the independent Commonwealth statutory authority, the Australian Electoral Commission. [3]

Procedure

Under the full-preference instant-runoff voting system, in each seat, the candidate with the lowest vote is eliminated and their preferences are distributed; this process repeats until only two candidates remain. Whilst every seat has a TCP result, seats where the major parties have come first and second are commonly referred to as having a TPP result. In a TCP contest between Labor and the NSW/Vic Nationals and without a Liberal candidate, this is also considered a TPP, with the Nationals in these states considered a de facto major party within the Liberal/National Coalition. In seats where the major parties do not come first and second, differing TPP and TCP results are returned. When only one of two major parties contest a seat, such as at some by-elections, only a TCP result is produced. Swings in Australian parliaments are more commonly associated with the TPP vote. At the 2013 federal election, 11 of 150 seats returned differing TPP and TCP figures ("non-classic seats"), indicating a considerable two-party system. [4]

The tallying of seat TPP results gives a statewide and/or national TPP vote. Non-classic seats have votes redistributed for informational purposes to the major parties so that every seat has a TPP result. Whilst the TCP is the determining factor in deciding which candidate wins a seat, the overall election TPP is statistical and indicative only, as swings in seats are not uniform, and a varying range of factors can influence marginal-seat wins with single-member electorates. Several federal elections since 1937 have seen a government elected with a minority of the TPP vote: 1940 (49.7%), 1954 (49.3%), 1961 (49.5%), 1969 (49.8%), 1990 (49.9%) and 1998 (49.0%).

As the TPP vote rather than the primary vote is a better indicator of who is in front with seats won and lost on a preferential basis, Australian opinion polls survey voter intention with a TPP always produced. However, these TPP figures tend to be calculated based on preference flows at the previous election rather than asked at the time of polling. The difference between the two is usually within the margin of error (usually +/– 3 percentage points). History has shown that prior-election preference flows are more reliable. [5]

Analysis

After the count has taken place, it is possible to analyze the ultimate preference flows for votes cast for the parties that were ultimately excluded from the TPP calculation, in order to determine if the composite flow would have significantly affected the final result. Such an exercise is shown for the 2017 by-election in Bennelong:

2017 Bennelong by-election - Preference Flow Data [6]
PartyCandidateFirst preferences% preference to
Votes%LiberalLabor
  Greens Justin Alick5,6886.819.780.3
  Conservatives Joram Richa3,6094.386.513.5
  Christian Democrats Gui Dong Cao2,6263.172.427.6
  Science James Jansson1,0411.239.460.6
  Sustainable Australia Wesley Folitarik9951.248.951.1
  Affordable Housing Anthony Ziebell7410.944.755.3
  Liberty Alliance Tony Robinson7190.979.021.0
  Progressives Chris Golding4250.542.157.9
  People's Party James Platter1860.248.951.1
  Non-Custodial Parents Anthony Fels 1320.256.143.9
Totals16,16219.251.248.8

Preference Flows in Federal Elections

2019 Australian federal election - Preference Flow Data [7]
PartyFirst preferences% preference to
Votes%LiberalLabor
  Greens 1,482,92310.4017.882.2
  United Australia Party 488,8173.4365.134.9
  Independent 479,8363.3740.659.4
  One Nation 438,5873.0865.234.8
  Christian Democrat 116,6750.6874.425.6
  Conservative Nationals 77,2030.5471.828.2
  Katter's Australia 69,7360.4967.033.0
  Centre Alliance 46,9310.3332.967.1
  Shooters, Fishers, Farmers 41,4790.2959.140.9
  Sustainable Australia 35,6180.2546.054.0
  Liberal Democrats 34,6660.2477.222.8
  Justice 26,8030.1946.253.8
  Western Australia 25,2980.1849.051.0
  Australian Christians 23,8020.1780.819.2
  Democratic Labour 18,2870.1339.860.2
  Rise Up Australia 18,2870.1060.439.6
  Science 12,6170.0932.567.5
  Victorian Socialists 12,4530.0912.487.6
  Reason 8,8950.0631.268.8
  Progressives 7,7590.0532.867.2
  Australia First 6,7860.0556.443.6
  Great Australian 5,3550.0453.146.9
  CEC 3,2670.0226.473.6
  Socialist Equality 2,8660.0236.963.1
  Socialist Alliance 2,4470.0220.279.8
 Non-Affiliated2,1430.0232.467.6
  Better Families 2,0720.0164.135.9
  Australian Democrats 2,0390.0130.969.1
  Workers 1,6760.0158.741.3
  Love Australia or Leave 1,5640.0154.545.5
  Child Protection 1,2190.0145.454.6
  Non-Custodial Parents 1,2130.0151.348.7
  Involuntary Medication Objectors 1,1790.0136.463.6
  Flux 6020.0046.253.8

Examples

Federal, Swan 1918

1918 Swan by-election: Division of Swan, Western Australia
PartyCandidateVotes%±%
Labor Edwin Corboy 6,54034.4N/A
Country Basil Murray5,97531.4N/A
Nationalist William Hedges 5,63529.6N/A
Independent William Watson 8844.6N/A
Turnout 19,21364.3%
Labor gain from Nationalist Swing N/A

The result of the 1918 Swan by-election, the first-past-the-post election which caused the government of the day to introduce full-preference instant-runoff voting, under which Labor would have been easily defeated. Labor won the seat, and their majority was 3.0 points (34.4 minus 31.4). No swings are available as the Nationalists retained the seat unopposed at the previous election.

Federal, Adelaide 2004

2004 Australian federal election: Division of Adelaide, South Australia
PartyCandidateVotes%±%
Liberal Trish Worth 38,53045.29+0.82
Labor Kate Ellis 35,66641.92+5.50
Greens Jake Bugden6,7947.99+2.02
Family First Peter G Robins1,7532.06+2.06
Democrats Richard Pascoe1,3551.59–9.30
Independent Amanda Barlow9781.15+1.15
Total formal votes85,07695.60+0.66
Informal votes3,9204.40–0.66
Turnout 88,99693.62–1.09
Two-party-preferred result
Labor Kate Ellis 43,67151.33+1.95
Liberal Trish Worth 41,40548.67–1.95
Labor gain from Liberal Swing +1.95

It can be seen that the Liberal candidate had a primary vote lead over the Labor candidate. In a first-past-the-post vote, the Liberals would have retained the seat, and their majority would be said to be 3.4 points (45.3 minus 41.9).

However, under full-preference instant-runoff voting, the votes of all the minor candidates were distributed as follows:

2nd count: Barlow 978 votes distributed
PartyCandidateAdded votes%Votes%
Liberal Trish Worth 17217.638,70245.5
Labor Kate Ellis 20621.135,87242.2
Greens Jake Bugden36537.37,1598.4
Family First Peter G Robins969.81,8492.2
Democrats Richard Pascoe13914.21,4941.8
Total97885,076
3rd count: Democrats 1,494 votes distributed
PartyCandidateAdded votes%Votes%
Liberal Trish Worth 34323.039,04545.9
Labor Kate Ellis 49433.136,36642.8
Greens Jake Bugden56037.57,7199.1
Family First Peter G Robins976.51,9462.3
Total1,49485,076
4th count: Family First 1,946 votes distributed
PartyCandidateAdded votes%Votes%
Liberal Trish Worth 1,09856.440,14347.2
Labor Kate Ellis 37719.436,74343.2
Greens Jake Bugden47124.28,1909.6
Total1,94685,076
5th count: Greens 8,190 votes distributed – final TPP/TCP
PartyCandidateAdded votes%Votes%
Labor Kate Ellis 6,92884.643,67151.3
Liberal Trish Worth 1,26215.441,40548.7
Total8,19085,0761.3

The process of allocating the votes can be more succinctly shown thus:

2004 Australian federal election: Division of Adelaide, South Australia
Allocation of votes by count
PartyCandidateCount
1st2nd3rd4th5thTotal
  Labor Kate Ellis 35,6662064943776,92843,671
  Liberal Trish Worth 38,5301723431,0981,26241,405
  Greens Jake Bugden6,794365560471(8,190) 
  Family First Peter G Robins1,7539697(1,946)  
  Democrats Richard Pascoe1,355139(1,494)   
  Independent Amanda Barlow978(978)    

Thus, Labor defeated the Liberals, with 85 percent of Green and Green-preferenced voters preferencing Labor on the last distribution. Labor's TPP/TCP vote was 51.3 percent, a TPP/TCP majority of 1.3 points, and a TPP/TCP swing of 1.9 points compared with the previous election.

South Australia, Frome 2009

2009 Frome state by-election: Electoral district of Frome, South Australia [8] [9]
PartyCandidateVotes%±%
Liberal Terry Boylan7,57639.24–8.86
Labor John Rohde5,04126.11–14.93
Independent Geoff Brock 4,55723.60+23.60
National Neville Wilson1,2676.56+6.56
Greens Joy O'Brien7343.80+0.06
One Nation Peter Fitzpatrick1340.69+0.69
Total formal votes19,30997.12+0.21
Informal votes5732.88–0.21
Turnout 19,88289.79–4.44
Two-party-preferred result
Liberal Terry Boylan9,97651.67–1.74
Labor John Rohde9,33348.33+1.74
Two-candidate-preferred result
Independent Geoff Brock 9,98751.72+51.72
Liberal Terry Boylan9,32248.28–5.13
Independent gain from Liberal Swing N/A

The 2009 Frome by-election was closely contested, with the result being uncertain for over a week. [10] [11] [12] Liberal leader Martin Hamilton-Smith claimed victory on behalf of the party. [13] [14] [15] The result hinged on the performance of Brock against Labor in the competition for second place. Brock polled best in the Port Pirie area, and received enough eliminated candidate preferences to end up ahead of the Labor candidate by 30 votes.

Distribution of Preferences – 4th count [16]
PartyCandidateVotes%±%
Liberal Terry Boylan8,21542.54
Independent Geoff Brock 5,56228.81
Labor John Rohde5,53228.65

Brock received 80 percent of Labor's fifth count preferences to achieve a TCP vote of 51.72 percent (a majority of 665 votes) against the Liberal candidate. [17] [18] The by-election saw a rare TPP swing to an incumbent government, and was the first time an opposition had lost a seat at a by-election in South Australia. [19] [20] The result in Frome at the 2010 state election saw Brock come first on primary votes, increasing his primary vote by 14.1 points to a total of 37.7 percent and his TCP vote by 6.5 points to a total of 58.2 percent. Despite a statewide swing against Labor at the election, Labor again increased its TPP vote in Frome by 1.8 points to a total of 50.1 percent.

Federal, Melbourne 2010

2010 Australian federal election: Division of Melbourne, Victoria
PartyCandidateVotes%±%
Labor Cath Bowtell34,02238.09–11.42
Greens Adam Bandt 32,30836.17+13.37
Liberal Simon Olsen18,76021.00–2.49
Sex Party Joel Murray1,6331.83+1.83
Family First Georgia Pearson1,3891.55+0.55
Secular Penelope Green6130.69+0.69
Democrats David Collyer6020.67–0.76
Total formal votes89,32796.38–0.82
Informal votes3,3563.62+0.82
Turnout 92,68390.09–1.41
Two-party-preferred result
Labor Cath Bowtell65,47373.30+1.03
Liberal Simon Olsen23,85426.70–1.03
Two-candidate-preferred result
Greens Adam Bandt 50,05956.04+10.75
Labor Cath Bowtell39,26843.96–10.75
Greens gain from Labor Swing +10.75

In this example, the two remaining candidates/parties, one a minor party, were the same after preference distribution at both this election and the previous election. Therefore, differing TPP and TCP votes, margins, and swings resulted. [21]

South Australia, Port Adelaide 2012

2012 Port Adelaide state by-election: Electoral district of Pt Adelaide, South Australia
PartyCandidateVotes%±%
Labor Susan Close 8,21842.3–7.6
Independent Gary Johanson4,71724.3+24.3
Independent Sue Lawrie2,93815.1+15.1
Liberal Democrats Stephen Humble1,4157.3+7.3
Greens Justin McArthur1,0965.6–0.6
Independent Colin Thomas3141.6+1.6
Independent Bob Briton2921.5+1.5
One Nation Grant Carlin2691.4+1.4
Democratic Labor Elizabeth Pistor1510.8+0.8
Total formal votes19,41092.8–3.8
Informal votes1,5057.2+3.8
Turnout 20,91582.8–10.4
Two-candidate-preferred result
Labor Susan Close 10,27752.9–9.8
Independent Gary Johanson9,13347.1+47.1
Labor hold Swing N/A

At the 2012 Port Adelaide state by-election, only a TCP could be produced, as the Liberal Party of Australia (and Family First Party and independent candidate Max James), who contested the previous election and gained a primary vote of 26.8 percent (and 5.9 percent, and 11.0 percent respectively), did not contest the by-election. On a TPP margin of 12.8 points from the 2010 election, considered a safe margin on the current pendulum, Labor would probably have retained their TPP margin based on unchanged statewide Newspoll since the previous election. Labor retained the seat on a 52.9 percent TCP against Johanson after the distribution of preferences. [22] [23] [24]

Unlike previous examples, neither a TPP or TCP swing can be produced, as the 2010 result was between Labor and Liberal rather than Labor and independent with no Liberal candidate. An increase or decrease in margins in these situations cannot be meaningfully interpreted as swings. As explained by the ABC's Antony Green, when a major party does not contest a by-election, preferences from independents or minor parties that would normally flow to both major parties does not take place, causing asymmetric preference flows. Examples of this are the 2008 Mayo and 2002 Cunningham federal by-elections, with seats returning to TPP form at the next election. [25] This contradicts News Ltd claims of large swings and a potential Liberal Party win in Port Adelaide at the next election. [26] [27]

House of Representatives primary, two-party and seat results

A two-party system has existed in the Australian House of Representatives since the two non-Labor parties merged in 1909. The 1910 election was the first to elect a majority government, with the Australian Labor Party concurrently winning the first Senate majority. Prior to 1909 a three-party system existed in the chamber. A two-party-preferred vote (2PP) has been calculated since the 1919 change from first-past-the-post to preferential voting and subsequent introduction of the Coalition. ALP = Australian Labor Party, L+NP = grouping of Liberal/National/LNP/CLP Coalition parties (and predecessors), Oth = other parties and independents.

House of Representatives results and polling
Election
Year
Labour Free Trade Protectionist Independent Other
parties
Total
seats
1st 19011428312 75
Election
Year
Labour Free Trade Protectionist Independent Other
parties
Total
seats
2nd 1903232526 1 Revenue Tariff 75
Election
Year
Labour Anti-Socialist Protectionist Independent Other
parties
Total
seats
3rd 190626262111 Western Australian 75
Primary vote2PP voteSeats
ALPL+NPOth.ALPL+NPALPL+NPOth.Total
13 April 1910 election 50.0%45.1%4.9%4231275
31 May 1913 election 48.5%48.9%2.6%3738075
5 September 1914 election 50.9%47.2%1.9%4232175
5 May 1917 election 43.9%54.2%1.9%2253075
13 December 1919 election 42.5%54.3%3.2%45.9%54.1%2538275
16 December 1922 election 42.3%47.8%9.9%48.8%51.2%2940675
14 November 1925 election 45.0%53.2%1.8%46.2%53.8%2350275
17 November 1928 election 44.6%49.6%5.8%48.4%51.6%3142275
12 October 1929 election 48.8%44.2%7.0%56.7%43.3%4624575
19 December 1931 election 27.1%48.4%24.5%41.5%58.5%14501175
15 September 1934 election 26.8%45.6%27.6%46.5%53.5%18421474
23 October 1937 election 43.2%49.3%7.5%49.4%50.6%2943274
21 September 1940 election 40.2%43.9%15.9%50.3%49.7%3236674
21 August 1943 election 49.9%23.0%27.1%58.2%41.8%4919674
28 September 1946 election 49.7%39.3%11.0%54.1%45.9%4326574
10 December 1949 election 46.0%50.3%3.7%49.0%51.0%47740121
28 April 1951 election 47.6%50.3%2.1%49.3%50.7%52690121
29 May 1954 election 50.0%46.8%3.2%50.7%49.3%57640121
10 December 1955 election 44.6%47.6%7.8%45.8%54.2%47750122
22 November 1958 election 42.8%46.6%10.6%45.9%54.1%45770122
9 December 1961 election 47.9%42.1%10.0%50.5%49.5%60620122
30 November 1963 election 45.5%46.0%8.5%47.4%52.6%50720122
26 November 1966 election 40.0%50.0%10.0%43.1%56.9%41821124
25 October 1969 election 47.0%43.3%9.7%50.2%49.8%59660125
2 December 1972 election 49.6%41.5%8.9%52.7%47.3%67580125
18 May 1974 election 49.3%44.9%5.8%51.7%48.3%66610127
13 December 1975 election 42.8%53.1%4.1%44.3%55.7%36910127
10 December 1977 election 39.7%48.1%12.2%45.4%54.6%38860124
18 October 1980 election 45.2%46.3%8.5%49.6%50.4%51740125
5 March 1983 election 49.5%43.6%6.9%53.2%46.8%75500125
1 December 1984 election 47.6%45.0%7.4%51.8%48.2%82660148
11 July 1987 election 45.8%46.1%8.1%50.8%49.2%86620148
24 March 1990 election 39.4%43.5%17.1%49.9%50.1%78691148
11 Mar 1993 Newspoll44%45%11%49.5%50.5%
13 March 1993 election 44.9%44.3%10.7%51.4%48.6%80652147
28–29 Feb 1996 Newspoll40.5%48%11.5%46.5%53.5%
2 March 1996 election 38.7%47.3%14.0%46.4%53.6%49945148
30 Sep – 1 Oct 1998 Newspoll44%40%16%53%47%
3 October 1998 election 40.1%39.5%20.4%51.0%49.0%67801148
7–8 Nov 2001 Newspoll38.5%46%15.5%47%53%
10 November 2001 election 37.8%43.0%19.2%49.0%51.0%65823150
6–7 Oct 2004 Newspoll39%45%16%50%50%
9 October 2004 election 37.6%46.7%15.7%47.3%52.7%60873150
20–22 Nov 2007 Newspoll44%43%13%52%48%
24 November 2007 election 43.4%42.1%14.5%52.7%47.3%83652150
17–19 Aug 2010 Newspoll36.2%43.4%20.4%50.2%49.8%
21 August 2010 election 38.0%43.3%18.7%50.1%49.9%72726150
3–5 Sep 2013 Newspoll33%46%21%46%54%
7 September 2013 election 33.4%45.6%21.0%46.5%53.5%55905150
28 Jun – 1 Jul 2016 Newspoll35%42%23%49.5%50.5%
2 July 2016 election 34.7%42.0%23.3%49.6%50.4%69765150
15–16 May 2019 Newspoll37%39%25%51.5%48.5%
18 May 2019 election 33.3%41.4%25.2%48.5%51.5%68776151
Polling conducted by Newspoll and published in The Australian. Three percent margin of error.

See also

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1990 Australian federal election

The 1990 Australian federal election was held in Australia on 24 March 1990. All 148 seats in the House of Representatives and 40 seats in the 76-member Senate were up for election. The incumbent Australian Labor Party led by Bob Hawke defeated the opposition Liberal Party of Australia led by Andrew Peacock with coalition partner the National Party of Australia led by Charles Blunt despite losing the two party preferred popular vote. The election saw the reelection of a Hawke government, the fourth successive term. This was the first, and to date only, time the Labor party won a fourth consecutive election.

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.

2010 South Australian state election

The 2010 South Australian state election elected members to the 52nd Parliament of South Australia on 20 March 2010. All seats in the House of Assembly or lower house, whose current members were elected at the 2006 election, and half the seats in the Legislative Council or upper house, last filled at the 2002 election, became vacant.

2008 Mayo by-election

The 2008 Mayo by-election was held for the Australian House of Representatives seat of Mayo, located in Adelaide, South Australia, on 6 September 2008, following the retirement of Liberal Party MP and former Liberal leader Alexander Downer. The by-election was held on the same day as the Lyne by-election, and the Western Australian state election.

2009 Frome state by-election

A by-election was held for the South Australian House of Assembly seat of Frome on 17 January 2009. This was triggered by the resignation of former Premier and state Liberal MHA Rob Kerin. The seat had been retained by the Liberals at the 2006 state election on a 3.4 per cent margin, and at the 2002 state election on an 11.5 per cent margin.

Geoffrey Graeme Brock is a South Australian politician, representing the seat of Frome in the South Australian House of Assembly as an independent since the 2009 Frome by-election. Following the 2014 election Brock was Minister for Regional Development and Minister for Local Government in the Weatherill Labor cabinet until it was defeated at the 2018 election.

2014 South Australian state election

The 2014 South Australian state election elected members to the 53rd Parliament of South Australia on 15 March 2014, to fill all 47 seats in the House of Assembly and 11 of 22 seats in the Legislative Council. The 12-year-incumbent Australian Labor Party (SA) government, led by Premier Jay Weatherill, won its fourth consecutive four-year term in government, a record 16 years of Labor government, defeating the opposition Liberal Party of Australia (SA), led by Opposition Leader Steven Marshall.

2012 Port Adelaide state by-election

A by-election occurred in the South Australian House of Assembly seat of Port Adelaide on 11 February 2012. Labor's Susan Close won the seat on a 52.9 percent two-candidate-preferred (TCP) vote. The by-election was triggered by the resignation of former Deputy Premier, Treasurer and state Labor MHA Kevin Foley.

2012 Ramsay state by-election

A by-election occurred in the South Australian House of Assembly seat of Ramsay on 11 February 2012. The seat was won by Labor candidate Zoe Bettison. The by-election was triggered by the resignation of former Premier and state Labor MHA Mike Rann.

2018 South Australian state election

The 2018 South Australian state election to elect members to the 54th Parliament of South Australia was held on 17 March 2018. All 47 seats in the House of Assembly or lower house, whose members were elected at the 2014 election, and 11 of 22 seats in the Legislative Council or upper house, last filled at the 2010 election, were contested. The record-16-year-incumbent Australian Labor Party (SA) government led by Premier Jay Weatherill was seeking a fifth four-year term, but was defeated by the opposition Liberal Party of Australia (SA), led by Opposition Leader Steven Marshall. Nick Xenophon's new SA Best party unsuccessfully sought to obtain the balance of power.

2014 Fisher state by-election

A by-election for the seat of Fisher in the South Australian House of Assembly was held on 6 December 2014. The by-election was triggered by the death of independent MP Bob Such on 11 October 2014. Originally elected to Fisher for the Liberal Party of Australia at the 1989 election, defeating the one-term Australian Labor Party MP Philip Tyler, Such left the party in 2000.

2015 North Sydney by-election

A by-election for the Australian House of Representatives seat of North Sydney was held on 5 December 2015 from 8 am to 6 pm AEDT.

References

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    "Labor Keeps Port Adelaide, Ramsay in South Australian by-elections". The Australian . 12 February 2012.
    "By-election swings carry 'message for Labor'". The Australian . 13 February 2012.