Proportional representation: Difference between revisions

'''Proportional representation''' ('''PR''') characterizes [[electoral system]]s in which divisions in an electorate are reflected proportionately in the elected body.<ref name=JSM7>{{cite book|last1=Mill|first1=John Stuart|author-link=John Stuart Mill|title=Considerations on Representative Government|chapter=Chapter VII, Of True and False Democracy; Representation of All, and Representation of the Majority only |chapter-url=http://www.gutenberg.org/files/5669/5669-h/5669-h.htm#link2HCH0007 |year=1861 |publisher=Parker, Son, & Bourn |location=London|title-link=Considerations on Representative Government}}</ref> The most widely used families of "proportional representation" electoral systems are [[party-list proportional representation|party-list PR]], the [[singlemixed-member transferableproportional voterepresentation]] (STVMMP), and the [[mixed-membersingle proportionaltransferable representationvote]] (MMPSTV).<ref name="DouglasHowPrElecWork">{{cite web|last=Amy|first=Douglas J|title=How Proportional Representation Elections Work |url=http://www.fairvote.org/how_proportional_representation_elections_work |publisher=[[FairVote]]| access-date=26 October 2017}}</ref>

[[Voting theorists]] frequently debate which systems can be called "proportional representation", and consider the levels of proportionality achieved by various systems from "low proportional" to "high proportional". The concept of "proportional representation" can be quantified as a measure of the outcome of an election where there are multiple parties and multiple members are elected, and the representatives are demographically similar to the voting population. It is one of many [[types of representation]] in a [[W:Representative government|representative government]].

Countries which have semi-proportional representation systems include: [[Australia]], [[Germany]], [[Hungary]], [[India]], [[Republic of Ireland]], [[Italy]], [[Japan]], [[Mexico]], [[New Zealand]], [[Thailand]] and [[Wales]]. [[India]] is one ofperhaps the mostlargest successfuldemocracy exampleswhich ofuses a countryform withof proportional representation.

Similar principles apply to sub-regions, who may have their own parliament or assembly. For example, in [[W:Scotland|Scotland]], after the passage of the [[W:Local Governance (Scotland) Act 2004|Local Governance (Scotland) Act 2004]], the Scottish portion of the [[United Kingdom]] uses [[single transferable vote]] to select many of their local representatives.

Whenever more than a [[Hare Quota]] of the voters gives max support to a single candidate and min support to every other candidate, that candidate is guaranteed to win regardless of how any of the other voters vote. This is explicitly formalized for approval ballots as [[Justified_representation#Proportional_justified_representation | Proportional justified representation ]].

In asset voting,<ref name=smithMultisurv/><ref name=smithAssetMultiwin>{{cite web|last=Smith|first=Warren|title="Asset voting" scheme for multiwinner elections|url=http://rangevoting.org/WarrenSmithPages/homepage/multiwin.pdf|date=8 March 2005}}</ref> the voters vote for candidates and then the candidates negotiate amongst each other and reallocate votes amongst themselves. Asset voting was proposed by [[Lewis Carroll]] in 1884<ref>{{cite web |url=https://archive.org/details/ThePrinciplesOfParliamentaryRepresentation |title=The Principles of Parliamentary Representation |last=Dodgson |first=Charles |date=1884 |publisher=London: Harrison and Sons |access-date=28 June 2019 |quote=The Elector must understand that, in giving his vote to ''A'', he gives it to him as his absolute property, to use for himself, or to transfer to other Candidates, or to leave unused.}}</ref> and has been more recently independently rediscovered and extended by [[Warren D. Smith]] and [[Forest Simmons]].<ref name=smithAssetWeb>{{cite web|last=Smith|first=Warren|title=Asset voting – an interesting and very simple multiwinner voting system|url=http://rangevoting.org/Asset.html|access-date=4 April 2016}}</ref> As such, this method substitutes candidates' collective preferences for those of the voters.

Similar to [[Majority Judgment]] voting that elects single winners, Evaluative Proportional Representation (EPR) elects all the members of a legislative body. Both systems remove the qualitative wasting of votes.<ref>{{cite book|author= M. Balinski & R. Laraki|year=2010|title=Majority Judgment. |publisher=MIT |isbn=978-0-262-01513-4}}</ref> Each citizen grades the fitness for office of as many of the candidates as they wish as either Excellent (ideal), Very Good, Good, Acceptable, Poor, or Reject (entirely unsuitable). Multiple candidates may be given the same grade by a voter. Using EPR, each citizen elects their representative at-large for a city council. For a large and diverse state legislature, each citizen chooses to vote through any of the districts or official electoral associations in the country. Each voter grades any number of candidates in the whole country. Each elected representative has a different voting power (a different number of weighted votes) in the legislative body. This number is equal to the total number of votes given exclusively to each member from all citizens. Each member's weighted vote results from receiving one of the following from each voter: their highest grade, highest remaining grade, or proxy vote. No citizen's vote is "[[wasted vote|wasted]]"<ref>{{cite journal |first1=Stephen |last1=Bosworth |first2=AnderAnders |last2=Corr |first3=Stevan |last3=Leonard |name-list-style=amp |title=Legislatures Elected by Evaluative Proportional Representation (EPR): an Algorithm |url=http://www.jpolrisk.com/legislatures-elected-by-evaluative-proportional-representation-epr-an-algorithm-v2/|journal=Journal of Political Risk |volume=7 |number=8 |date=July 8, 2019 |access-date=August 19, 2019}}</ref> Unlike all the other proportional representation systems, each EPR voter, and each self-identifying minority or majority is quantitatively represented with exact proportionality. Also, like Majority Judgment, EPR reduces by almost half both the incentives and possibilities for voters to use Tactical Voting. {{See also|Tactical voting#Majority judgment}}

SystemsA designedfew tocities havein highthe levelsUnited ofStates Proportionaluse representationSTV, doincluding havePortland, someOR, historyAlbany, inCA, thePalm UnitedDesert, StatesCA, Cambridge, MA, and [https://fairvote.org/our-reforms/proportional-ranked-choice-voting-information/ a couple of others]. Many cities in the past, including New York, oncealso had used such systems for their city councils as a way to break up the Democratic Party monopolies on elective office. In Cincinnati, Ohio, a system was adopted in 1925 to get rid of Republican party dominance but was successfully overturned in 1957.

Many of the properties of these systems can be derived from their party list simplifications. The [[Balinski–Young theorem]] implies that not all desirable properties are possible in the same system. Theile type systems reduce to [[Highest averages method|divisor methods]] which means that adding voters or winners will not change results in undesirable ways. The other three reduce to [[Largest remainder methods]] which obey Quota Rules but adding voters or winners may change outcomes in undesirable ways. One such way is failure of [[Participation criterion]]. It is not clear which is a fundamentally better choice since Quota Rules are inanimatelyintimately tied with some definitions of proportionality.

Some common criticisms of [[STV]] (which would likely hold for many other nonpartisan PR methods) are that it is too complex in terms of filling out the ballot and tabulation, that it takes too long to count compared to partisan PR methods (many of which are [[Precinctprecinct-summable]] due to being based on [[FPTP]]), and that it can even make representatives parochialist and focused on representing their multi-member districts rather than the state or nation as a whole. Note that this last criticism is inapplicable when nonpartisan PR methods are proposed for a single national/statewide district, though this is usually not proposed or done (with the exception of some 21-seaters in Australia).

Due to the ambiguity and difficulty in the definition of Proportional Representation academic work often uses another more robust metric. This is the concept of a [[Stable Winner Set]]. The requirement that a system always produces a stable winner set when there exists one is definable in all possible systems. This makes it more useful than the concept of Proportional Representation which is typically tied to Partisan voting and as such cannot be defined for all systems. This concept evolved out of the economics field of Participatory[[participatory Budgeting but can be equally suitable in Social Choice Theorybudgeting]]. A less strict and more practicalweaker version of this is given by [[Justifiedjustified representation]].

Almost all sequential PR methods can have a single-winner method done to elect the final seat; this is because at that point there is only one seat left to elect. See [[Single transferable vote#Deciding the election of the final seat]] for an example. [[Condorcet methods]] and [[STAR voting]] can be made to work with PR methods in this way.

** [https://www.fairvote.org/proportional_representation_libraryarchives/proportional-representation-library/ FairVote]

[[Category:Proportional voting methods|*]]