Reweighted range voting: Difference between revisions
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(I'm not sure if I should include this technicality because you can still use Sainte-Laguë reweighting with SPAV and and people will probably just call it a variant of SPAV) Tag: Undo |
Dr. Edmonds (talk | contribs) (It is almost always called reweighted range voting) Tag: New redirect |
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#REDIRECT [[Reweighted Range Voting]] |
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Reweighted Score Voting, also known as '''Reweighted Range Voting''' ('''RRV'''), is a [[Multi-Member System | Multi-Member ]] [[Score voting]] System. It is the natural extension of the [[Jefferson Method]] to [[Multi-Member System]]. If two level score (ie [[Approval voting]]) ballots are used then it reduces to [https://en.wikipedia.org/wiki/Sequential_proportional_approval_voting Sequential Proportional Approval Voting]. |
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==Procedure== |
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Each voter submits a ballot which, for each candidate, indicates a numeric score which is less than or equal to some maximum number MAX. |
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Each ballot is given an initial "weight" of 1. |
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1. The highest scoring candidate wins the first seat. |
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2. When a candidate wins, all ballots supporting that candidate are then reweighted, resulting in reduced vote weight going forward for voters who have successfully helped to elect a candidate. This reweighting happens in proportion to the amount of support given in order to ensure that all voters have an equitable amount of influence on the election |
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'''Reweighted ballot = 1/(1+SUM/MAX), where SUM is the sum of the scores that ballot gives to the winners-so-far''' |
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3. The remaining candidate with the highest total reweighted score wins, and the process is repeated until all available seats have been filled. |
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See http://www.rangevoting.org/RRV.html for more details (some of the wording on this page is taken from there). A variant is to use the reweighting formula 0.5/(0.5 + SUM/MAX). |
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== Reweighting Variations == |
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One variation is to use the reweighting formula 1/(1 + SUM/MAX). This variant reduces to D'Hondt when voters vote on party lines. |
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Another variant is to use the reweighting formula 0.5/(0.5 + SUM/MAX), or equivalently, 1/(1 + 2*SUM/MAX). This variant reduces to Sainte-Laguë when voters vote on party lines. |
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There is an infinite number of variants that all use the fallowing formula: K/(K + SUM/MAX) where ½≤K≤1. The two above formulas are special cases for when K equals 1 and ½. |
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== Method Variations == |
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A 5 STAR variation in which a final runoff is performed for the last seat available has been proposed in order to incentivize voters to more honestly express their preference order and degree of support. |
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Each voter submits a ballot in which candidates are scored from 0 (worst) to 5 (best.) |
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Each ballot is given an initial "weight" of 1. |
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1. The highest scoring candidate wins the first seat. |
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2. When a candidate wins, all ballots supporting that candidate are then reweighted, resulting in reduced vote weight going forward for voters who have successfully helped to elect a candidate. This reweighting happens in proportion to the amount of support given in order to ensure that all voters have an equitable amount of influence on the election |
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'''Reweighted ballot = 1/(1+2*SUM/5), where SUM is the sum of the scores that ballot gives to the winners-so-far''' |
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3. The remaining candidate with the highest total reweighted score wins each seat available- up until the final seat up for election. |
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4. For the final seat available, the two highest scoring candidates remaining runoff, with the candidate preferred (scored higher) by more reweighted ballots winning the final seat. |
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[[Category:Cardinal voting methods]] |
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[[Category:Proportional voting methods]] |
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[[Category:Multi-winner voting methods]] |
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Revision as of 05:38, 9 February 2020
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