Multi-member system: Difference between revisions

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Multi member voting methods, also called multi winner methods, are voting methods which elect multiple people in one election. It is common for several of these voting methods to be combined into a [[Regional System]].
 
==Bloc Votingvoting Methodsmethods==
 
[[Block voting|Bloc methods]] find the candidate set with the most support or the most votes overall using the same metric which would be used in a [https://electowiki.org/wiki/Single_Member_system single member system]. The number of seats up for election is determined and the top candidates are elected to fill those seats.
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*'''Bloc Plurality Voting''': Each voter chooses as many candidates as there are seats to be elected. Add all the votes. Elect the candidates with the most votes until all positions are filled.
 
==Sequential [[Proportional representation|Proportionalproportional]] Methodsmethods==
Sequential Cardinal Methods elect winners one at a time in sequence using a candidate selection method and a reweighting mechanism. The single-winner version of the selection is applied to find the first winner, then a reweighting is applied before the selection of the next and subsequent winners. A reweighting is applied to either the ballot or the scores for the ballot itself. The purpose of the reweighting phase is to ensure outcomes have a high level of [[Proportional representation]] by requiring them to satisfy criteria like the [[Proportional representation|Hare Quota Criterion]].
 
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* [[Sequential Monroe voting]]
* [[Allocated Score]]
* [[Sequentially SubtractedSpent Score]]
* [[Single transferable vote]]
* [[Single distributed vote]]
* [[Sequential Ebert]]
 
== Optimal [[Proportional representation|Proportionalproportional]] Methodsmethods ==
 
[https://rangevoting.org/QualityMulti.html Optimal] Systems select all winners at once by optimizing a specific desirable metric for proportionality. First a "quality function" or desired outcome is determined, and then an algorithm is used to determine the winner set that best maximizes that outcome. In most systems this is done by permuting to all possible winner sets not a [[w:Mathematical optimization|maximization algorithm]]. This makes such systems computationally expensive. Since ranks do not allow for the arithmatic operations to do such calculations. As such there are no optimal [[Ordinal voting]] systems but only optimal [[Cardinal voting systems]]
 
Optimal ordinal methods may either be based on [[weighted positional method|weighted positional methods]], like [[Monroe's method]], or extend the notion of a Condorcet winner to a winning set, like [[Schulze STV]].
 
Common examples:
* [[CPO-STV]]
* [[Schulze STV]]
* [https://rangevoting.org/QualityMulti.html Harmonic Voting]
* [[Proportional approval voting]]
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* [[PAMSAC]]
 
== Local Districtdistrict Clustersclusters vs Multimulti-Membermember Districtsdistricts ==
 
Local District Clusters offer an alternative to running a multi-winner voting method in a Multi-Member District. Traditional multi-member districts take single-member districts and combine them, whilewith thisall methodcandidates wouldelected at-large. In contrast, Local District Clusters link themdistricts into a multi-member cluster which runs a single election, but then elects only one candidate from each district.
 
For example: In a five winner election, five single-member districts would be linked into a cluster. As usual, most major parties could still be expected to run five candidates. In this “Local” system, each candidate would be elected to a specific single-member district inside their cluster. Using votes from the cluster's full electorate, the first winner would be selected and would be designated as the winner in their home district. All other candidates running in that district would then be eliminated, and the selection rounds would continue until all the seats have been filled and until each district has a designated representative.
 
All multi-winner voting methods, including multi-member and proportional methods, can be adapted to run in local clusters. The purported inventor of this alternative is Byron Becker for his [http://localpr.ca/basics/overview/ Local PR system]. Although, it is unclear if [[Fair majority voting]] which also uses Local District Clusters predates [http://localpr.ca/basics/overview/ Local PR system] or not.
 
===Pros===
 
* Improved [[Proportionate representation]]: EachOnce elected, each elected representative is responsible for a smaller area, and can focus on the specific issues important to the citizens of that region district.
* Improved [[Petitioner Accountability]]: Each citizenvoter fromin thateach district has a specific representative for local issues who they can behold heldaccountable tofor account. ielocal issues withsuch as traffic/, schools/, hospitals, can'tetc. haveFor theissues buckwhere passeda byvoters blaming otherlocal representative. Fordoesn't partisanalign issueswith theythem, wouldvoters could go to the representativeelected official or officials in their cluster who isthey mostvoted likelyfor partisan or issue based representation. Candidates who fail to agreedeliver withon thempromises, likeeither into STVtheir district or to their larger supporter base across the cluster would be easier to vote out, assuming that their supporter base or local electorate wasn't satisfied by their record.
 
===Cons===
 
All the "best" candidates may be running in one district, soand when ita iswinner wonin theythat dondistrict'ts competerepresentative inis otherrepresented, races.the Theother partiescandidates wouldin havethat todistrict decidecan whonot to run in whatwin ridingelsewhere. ItFor haspartisan beenimplementations, arguespolitical thatparties a system where representativewould have to attake leastinto haveaccount astrategic mailingnomination addressconsiderations into thedecide riding they hopewho to representrun isin importantwhat for representationdistrict. In the last 2015 Canadian federal election an MP won a district without having a mailing address in Canada.
 
[[Category:Multi-winner voting methods]]
[[Category:Types of representation]]
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