Redistribution (Australia)

In Australia, a redistribution is the process of redrawing the boundaries of electoral divisions for the House of Representatives arising from changes in population and changes in the number of representatives. There is no redistribution for the Senate as each State constitutes a division, though with multiple members. The Australian Electoral Commission, an independent statutory authority, oversees the redistribution process for federal divisions, taking into account a number of factors. Politicians, political parties and the public may make submissions to the AEC on proposed new boundaries, but any interference with their deliberations is considered a serious offence.

Section 24 of the Constitution of Australia specifies that the number of members of the House of Representatives in each state is to be calculated from their population, although a minimum of five members is guaranteed for each state regardless of population. This minimum condition is only met by Tasmania, the smallest state. Representation of territories has been specified by subsequent laws. After the number of members for each state and territory is determined, in a process called apportionment or determination, the state and territory is divided into that number of electoral divisions.

A redistribution (sometimes called redrawing or "revision") of the geographic boundaries of divisions in a state or territory takes place when an apportionment determination results in a change in the number of seats to which a state or territory is entitled, at least once every seven years, or sooner when the AEC determines that population shifts within a state or territory have caused some seats to have too many or too few voters. The Commonwealth Electoral Act 1918 requires that all electoral divisions within a state or territory have approximately an equal numbers of enrolled voters. The Commonwealth Electoral Act (No. 2) 1973 reduced the allowed variation of electors in each division to 10% of the state or territory's average, down from 20%. New boundaries apply only to general elections held after the redistribution process has been completed, and by-elections are held on the previous electoral boundaries.

Each state and territory has its own commission which follows similar but not identical processes and principles for determining electoral boundaries and conducting elections within their jurisdiction, and those of local governments.

Total number of members

Section 24 of the Constitution of Australia requires that the total number of members of the Australian House of Representatives shall be "as nearly as practicable" twice as many as the number of members of the Australian Senate. There is presently a total of 76 senators: 12 senators from each of the six states and two from each of the two autonomous internal territories (the Australian Capital Territory and the Northern Territory). Since the 2019 federal election, there are 151 members of the House of Representatives.

The total number of members of the Australian House of Representatives, and consequently electorates, has increased from time to time. Every time there is an increase in the number of members, a redistribution is required to be undertaken, except in Tasmania which has always had the constitutional minimum number of five members. At the first federal election there were 65 members of the House of Representatives. In 1949, the number was increased from 74 to 121 (excluding the Australian Capital Territory and the Northern Territory), and in 1984 it was increased from 125 to 148. Following the 2017 reapportionment, the total number of members increased from 150 to 151.

Apportionment of seats

The AEC determines the number of members to which each state and territory is entitled. The Australian Bureau of Statistics officially communicates to the AEC the estimated population of each state and territory a year after each election. Based on these figures, the AEC makes its determination one year and one day after the first sitting day for a new House of Representatives. A redistribution is postponed if it would begin within one year of the expiration of the House of Representatives, to prevent a general election from occurring while a redistribution is in progress.

The last apportionment determination was made in July 2020, and the resulting redistribution is to take place during 2021, in time for the next federal election. In this apportionment, Western Australia lost a seat and Victoria gained a seat. The previous apportionment was in 2018, in time for the 2019 federal election. In that apportionment, Victoria and the Australian Capital Territory each gained one seat, and South Australia lost a seat. The total number of seats in the House of Representatives increased to 151.

States

Section 24 of the Constitution requires that electorates be apportioned among the states in proportion to their respective populations; provided that each Original State has at least 5 members in the House of Representatives. Section 29 of the Constitution forbids electorate boundaries from crossing state lines, and the Commonwealth Electoral Act 1918 sets out further requirements.

The AEC calculates the number of members/divisions for a state as follows:

${\mbox{Population quota}}={\frac {\mbox{Total population of the six states}}{\mbox{Number of Senators for the states x 2}}}$

${\mbox{Quotient of each state}}={\frac {\mbox{Population of each state }}{\mbox{Population quota}}}$

The entitlement of each state is the quotient rounded to the nearest whole number. However, each Original State is entitled to a minimum of 5 members, a provision that gives Tasmania two additional seats than its population would justify.

Territories

Prior to 2020, the quotient and entitlement of each territory were obtained using the same or similar method used for the states. Northern Territory and Australian Capital Territory were each entitled to a minimum of 1 member under section 48(2B) of the Commonwealth Electoral Act 1918. Since 2003, a statistical error margin equal to twice the standard error of the population estimate had been applied to territories. This margin was provided by the Australian Bureau of Statistics. The quotient and the error margin were added and rounded off to the nearest whole number to determine the entitlement for the territory. These provisions enabled the Northern Territory to retain its second seat at the 2004 federal election, and the Australian Capital Territory to gain a third seat at the 2019 federal election.

The Electoral Amendment (Territory Representation) Act 2020, passed on 9 December 2020, amended the Commonwealth Electoral Act 1918 to apply the "harmonic mean method" in calculating the entitlement determination for the territories, and continues to use the same population quota as the states. The inclusion of the standard error margin was abolished.

The calculation of the entitlement of each territory is:

${\mbox{Quotient of each territory}}={\frac {\mbox{Population of each territory }}{\mbox{Population quota}}}$

${\mbox{Minimum number of members}}={\mbox{Quotient rounded down to the nearest whole number}}$

${\mbox{Harmonic mean}}={\frac {\mbox{2 x Minimum number of members x (Minimum number of members + 1)}}{\mbox{Minimum number of members + (Minimum number of members + 1)}}}$

If the quotient of each territory is larger than its corresponding harmonic mean, then the entitlement is the quotient rounded up to the nearest whole number; otherwise, the entitlement is the quotient rounded down to the nearest whole number.

Seat Entitlement for Territories

Quotient	Minimum number of members	Harmonic mean	Seat Entitlement
1.0000 to 1.3332	1	1.3333	1
1.3333 to 1.9999			2
2.0000 to 2.3999	2	2.4000	2
2.4000 to 2.9999			3
3.0000 to 3.4285	3	3.4286	3
3.4286 to 3.9999			4
4.0000 to 4.4443	4	4.4444	4
4.4444 to 4.9999			5

Under the new method, the Northern Territory with a quota of 1.4332 will retain two seats at the next Australian federal election. It would have lost one seat under an AEC determination made in July 2020.

2020 reapportionment

The AEC made a determination in July 2020 under which the Northern Territory would lose one of its two lower house seats, Victoria will gain another seat, increasing from 38 to 39 seats, while Western Australia will lose one of its 16 seats. In December 2020, an amendment to the method for determining the apportionment for the territories had the effect of reversing the loss of the seat for the Northern Territory. The number of seats by States in the House of Representatives arising from the 2020 determination, with the change in law relating to the territories, were as follows:

State	Population June 2000 ('000)	Seats	Change
New South Wales	8,164.1	47
Victoria	6,694.9	39	1
Queensland	5,174.4	30
Western Australia	2,661.9	15	1
South Australia	1,769.3	10
Tasmania	540.6	5
State Total	25,005.2	146
Australian Capital Territory	431.1	3
Northern Territory	4.8	2
Other	245.9	-
Total	25,687.0	151

2017 reapportionment

The first sitting of the House of Representatives following the July 2016 election took place on 31 August 2016, and the three-year term was scheduled to expire on 29 August 2019. Following its timeline, the AEC on 31 August 2017 announced an apportionment determination following the completion of processing of the 2016 census. The determination resulted in a reduction of one seat in South Australia to 10, an increase of one seat in Victoria to 38 and an additional seat in the ACT to 3. The total number of members of the House of Representatives increased from 150 to 151 at the subsequent election in May 2019. The number of seats by States in the House of Representatives arising from the 2017 determination were as follows:

State	Seats	Change
New South Wales	47
Victoria	38	1
Queensland	30
Western Australia	16
South Australia	10	1
Tasmania	5
Australian Capital Territory	3	1
Northern Territory	2
Total	151	1

A draft redistribution in Victoria was released on 6 April 2018, and the final distribution was released on 12 July. There were also three scheduled redistributions of electoral boundaries, as seven years had elapsed since the last time these boundaries were reviewed.

2014 reapportionment

On 13 November 2014, the AEC made an apportionment determination that resulted in Western Australia's entitlement increasing from 15 to 16 seats, and New South Wales's decreasing from 48 to 47 seats. The number of seats by States in the House of Representatives arising from the 2014 determination were as follows:

State	Seats	Change
New South Wales	47	1
Victoria	37
Queensland	30
Western Australia	16	1
South Australia	11
Tasmania	5
Australian Capital Territory	2
Northern Territory	2
Total	150

A redistribution of electoral boundaries in New South Wales and Western Australia was undertaken before the 2016 election. The redistribution in New South Wales was announced on 16 October 2015, with the abolition of the Labor-held Division of Hunter. A redistribution also occurred in the Australian Capital Territory, as seven years had elapsed since the last time the ACT's boundaries were reviewed.

Historical apportionments

The historical apportionment of seats for the various states is:

State	1901	'03	'06	'13	'22	'34	'37	'49	'55	'68	'69	'74	'77	'80	'84	89	'92	'94	'97	'99	2000	'03	'05	'06	'08	'09	'10	'11	'16	'17	'18	'20
New South Wales	26		27		28			47	46	45			43		51		50				50		49			48			47
Victoria	23		22	20				33	33	34			33		39	38		37				37					37				38	39
Queensland	9			10				18	18		18		19		24		25	26	27			28		29		30					30
Western Australia	5							8	9			10			13	14					15								16			15
South Australia		7				6		10	11	12			10		13		12					11									10
Tasmania		5						5					5		5		5				5					5				5
Australian Capital Territory												2			2		2	3	2				2						2		3
Northern Territory												1									2				2					2
Total	75	75	75	75	75	74	74	121	122	124	125	127	124	125	148	148	147	148	148	148	150	150	150	150	150	150	150	150	150	150	151	151

Recent redistributions: 2016–2019

Australian Capital Territory

A redistribution of federal electoral divisions in the Australian Capital Territory commenced on 4 September 2017, due to changes in the territory's representation entitlement. The AEC released a proposed redistribution on 6 April 2018, and the final determination on 3 July 2018. The redistribution resulted in the creation of a third ACT electoral division named Bean (notionally fairly safe Labor), after historian Charles Bean.

Northern Territory

On 7 December 2016, the Electoral Commission for the Northern Territory announced the results of its deliberations into the boundaries of Lingiari and Solomon, the two federal electoral divisions in the Northern Territory. New boundaries gazetted from 7 February 2017 will see the remainder of the Litchfield Municipality and parts of Palmerston (the suburbs of Farrar, Johnston, Mitchell, Zuccoli and part of Yarrawonga) transferred from Solomon to Lingiari.

Queensland

A scheduled redistribution began in Queensland on 6 January 2017, and was finalised on 27 March 2018. Changes were made to the boundaries of 18 of Queensland's 30 electoral divisions, and no division names were changed.

South Australia

A South Australian seat was abolished due to population changes since the state's last redistribution in 2011. Although South Australia's population was still increasing, faster increases in other states saw a reduction in South Australia's representation from 11 to 10 seats. This was the third time South Australia lost a seat since the 1984 enlargement of the parliament, with Hawker abolished in 1993 and Bonython in 2004.

The redistribution in South Australia commenced on 4 September 2017. The proposed redistribution report was released on 13 April 2018, and the final determination on 26 June 2018. The AEC abolished the division of Port Adelaide. The hybrid urban-rural seat of Wakefield became the entirely urban seat of Spence, after Catherine Helen Spence. The more rural portions of Wakefield transferred to Grey and Barker.

Tasmania

A scheduled redistribution began in Tasmania on 1 September 2016. The determinations were announced on 27 September 2017, involved boundary changes, and the Division of Denison was renamed the Division of Clark.

Victoria

A redistribution of federal electoral divisions in Victoria commenced on 4 September 2017, due to changes in the state's representation entitlement. The determinations were announced on 20 June 2018, and created a 38th electoral division named Fraser (notionally a safe Labor).

Several divisions were also renamed: Batman to Cooper (after William Cooper), McMillan to Monash (after Sir John Monash), Melbourne Ports to Macnamara (after Dame Jean Macnamara) and Murray to Nicholls (after Sir Douglas and Lady Nicholls). A proposal to rename Corangamite to Cox (after swimming instructor May Cox) did not proceed.

The Coalition notionally lost the seat of Dunkley and Corangamite to Labor in the redistribution.

When redistribution required

A redistribution of State divisions is required in three circumstances:

• if there has been a change in the number of parliamentary representatives to which a State or Territory is entitled, due to a change in population or an increase in the overall number of members, subject to the minimum number of divisions in original States.
• if the number of electors in more than one third of the divisions in a State or one of the divisions in the ACT or Northern Territory deviates from the average State divisional enrolment by more than 10% for a period of more than two months.
• if seven years has elapsed since the previous redistribution.

Redistribution process

A redistribution is undertaken on a State-by-State basis. After the redistribution process commences, a Redistribution Committee — consisting of the Electoral Commissioner, the Australian Electoral Officer for the State concerned (in the ACT, the senior Divisional Returning officer), the State Surveyor General and the State Auditor General — is formed. The Electoral Commissioner invites public suggestions on the redistribution which must be lodged within 30 days. A further period of 14 days is allowed for comments on the suggestions lodged. The Redistribution Committee then divides the State or Territory into divisions and publishes its proposed redistribution. A period of 28 days is allowed after publication of the proposed redistribution for written objections. A further period of 14 days is provided for comments on the objections lodged. These objections are considered by an augmented Electoral Commission — consisting of the four members of the Redistribution Committee and the two part-time members of the Electoral Commission.

At the time of the redistribution the number of electors in the divisions may vary up to 10% from the 'quota' or average divisional figure but at a point 3.5 years after the expected completion of the redistribution, the figures should not vary from the average projected quota by more or less than 3.5%. Thus the most rapidly growing divisions are generally started with enrolments below the quota while those that are losing population are started above the quota.

Neither the Government nor the Parliament can reject or amend the final determination of the augmented Electoral Commission.

Management

See also: Australian electoral system § Gerrymandering and malapportionment

Boundaries for the Australian House of Representatives and for the six state and two territorial legislatures are drawn up by independent authorities, at the federal level by the Australian Electoral Commission (AEC) and in the states and territories by their equivalent bodies. Politicians have no influence over the process, although they, along with any other citizen or organisation, can make submissions to the independent authorities suggesting changes.

There is significantly less political interference in the redistribution process than is common in the United States. In 1978, federal Cabinet minister Reg Withers was forced to resign for suggesting to another minister that the name of a federal electorate be changed to suit a political ally.

There have been examples of malapportionment of federal and state electoral districts in the past, often resulting in rural constituencies containing far fewer voters than urban ones and maintaining in power those parties that have rural support despite polling fewer popular votes. Past malapportionments in Queensland, Western Australia and the 'Playmander' in South Australia were notorious examples of the differences between urban and rural constituency sizes than their population would merit. The Playmander distorted electoral boundaries and policies that kept the Liberal and Country League in power for 32 years from 1936 to 1968. In extreme cases, rural areas had four times the voting value of metropolitan areas. Supporters of such arrangements claimed Australia's urban population dominates the countryside and that these practices gave fair representation to country people.

Naming of divisions

The redistribution, creation and abolition of divisions is the responsibility of the AEC. When new divisions are created, the AEC will select a name. Most divisions are named in honour of prominent historical people, such as former politicians (often Prime Ministers), explorers, artists and engineers, and rarely for geographic places.

Some of the criteria the AEC uses when naming new divisions are:

• divisions are named after deceased Australians who have rendered outstanding service to their country, with consideration given to former Prime Ministers
• the original names of Divisions proclaimed at Federation in 1901 are to be retained where possible
• geographical place names are to be avoided
• Aboriginal names can be used as appropriate
• names that duplicate names of state electoral districts are not to be used.

Notional seat status

After a redistribution is carried out in a state or territory, the AEC calculates "notional" margins for the redistributed divisions by modelling the outcome of the previous election as if the new boundaries had been in place. These notional margins are used as the baseline for the electoral swings calculated and published in the AEC's virtual tally room at the following election. In some cases, the change in electoral boundaries can see the party which notionally holds the seat differ from the party which won it at the election.

External links

• Adam Carr's Electoral Archive: Index of House of Representatives Divisions 1901-2001