Difference between revisions of "Single-member district"

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(District Allocation)
 
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{{Wikipedia}}
 
{{Wikipedia}}
A '''single-member district''' or '''single-member constituency''' is an [[w:electoral district|electoral district]] that returns one officeholder to a body with multiple members such as a [[w:legislature|legislature]]. This is also sometimes called '''single-winner voting''' or '''winner takes all'''. The alternatives are [[Multi-Member System|multi-member district]]s, or the election of a body by the whole electorate voting as one constituency.
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A '''single-member district''' (SMD) or '''single-member constituency''' is an [[w:electoral district|electoral district]] that returns one officeholder to a body with multiple members such as a [[w:legislature|legislature]]. This is also sometimes called '''single-winner voting''' or '''winner takes all'''. The alternatives are [[Multi-Member System|multi-member district]]s, or the election of a body by the whole electorate voting as one constituency (i.e. [[proportional representation]]).
   
Many single member systems can be run independently in districts to form a [[Regional System]]. The systems:
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Many single member systems can be run independently in districts to form a [[Regional System]].
* [[Plurality voting]]: A valid vote can choose only one candidate
 
* [[Approval voting]]: A valid vote can only give a yes or nothing to a given candidate.
 
* [[Ordinal voting]]: A valid vote can rank candidates 1,2,3... (Tied rankings are permitted in some methods but not others)
 
* [[Cardinal voting]]: voting A valid vote allows independent numerical values to be associated with each candidate. (The set of valid values is limited.)
 
   
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There are two two key factors in single member representation: how the members are chosen (the voting method) and how the districts are drawn.
=Classification=
 
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==District Allocation==
 
They can be sub-classified by different ways to aggregate the ballots.
 
 
==[[Plurality voting]]==
 
 
There is only one way to combine plurality votes.
 
 
==[[Approval voting]] and [[Cardinal voting]]==
 
 
Since Approval is the degenerate case of Cardinal Ballots they have the same A sum would give the [[Utilitarian_winner]] while a median would give the majoritarian winner.
 
 
==[[Ordinal voting]]==
 
 
[[Borda count]] and [[Instant-runoff voting]] are common aggregation methods
 
   
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In most SMD systems, districts are divided by units of population, by administrative subregions, or other metrics to equalize representation (in theory).
   
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The process of changing the SMD boundaries is called '''redistricting'''. Changing districts for partisan gain is called [[Gerrymandering|'''gerrymandering''']].
 
==Popular Single Member systems==
 
==Popular Single Member systems==
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Single-winner voting methods can be sub-classified by different ways to aggregate the ballots.
 
* [[Plurality Voting]]: A valid vote can choose only one candidate
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*[[Plurality Voting]]: A valid vote can choose only one candidate
 
** [[Single Member Plurality]]
 
** [[Single Member Plurality]]
 
** [[Random ballot]]
 
** [[Random ballot]]
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; Automatic Truncation Line Option (ATLO) : A voter may mark a line in his/her ranking, meaning that if no one above the line wins, then that voter wants to drop from his/her ranking all of his/her below-line candidates and have a recount. (In pairwise-count methods the dropping only takes place if, additionally, there's a circular tie containing above-line and below-line candidates).
 
; Automatic Truncation Line Option (ATLO) : A voter may mark a line in his/her ranking, meaning that if no one above the line wins, then that voter wants to drop from his/her ranking all of his/her below-line candidates and have a recount. (In pairwise-count methods the dropping only takes place if, additionally, there's a circular tie containing above-line and below-line candidates).
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[[Category:Types of representation]]

Latest revision as of 13:39, 23 September 2021

Wikipedia has an article on:

A single-member district (SMD) or single-member constituency is an electoral district that returns one officeholder to a body with multiple members such as a legislature. This is also sometimes called single-winner voting or winner takes all. The alternatives are multi-member districts, or the election of a body by the whole electorate voting as one constituency (i.e. proportional representation).

Many single member systems can be run independently in districts to form a Regional System.

There are two two key factors in single member representation: how the members are chosen (the voting method) and how the districts are drawn.

District Allocation[edit | edit source]

In most SMD systems, districts are divided by units of population, by administrative subregions, or other metrics to equalize representation (in theory).

The process of changing the SMD boundaries is called redistricting. Changing districts for partisan gain is called gerrymandering.

Popular Single Member systems[edit | edit source]

Single-winner voting methods can be sub-classified by different ways to aggregate the ballots.

They can also be classified on how many times votes can be counted. Methods like Plurality, Borda, and Approval with single counting rounds are simpler since voters can be sure to know how their votes will be applied.

Single Winner Variations[edit | edit source]

Automatic Equal Ranking Line Option (AERLO)
A voter may mark a line in his/her ranking, meaning that if no one above that line wins, then that voter wants to promote to 1st place all of his/her above-line candidates and have a recount. (In pairwise-count methods the promotion only takes place if, additionally, there's a circular tie containing above-line and below-line candidates).
Automatic Truncation Line Option (ATLO)
A voter may mark a line in his/her ranking, meaning that if no one above the line wins, then that voter wants to drop from his/her ranking all of his/her below-line candidates and have a recount. (In pairwise-count methods the dropping only takes place if, additionally, there's a circular tie containing above-line and below-line candidates).