Allocated Score: Difference between revisions
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[[Allocated Score]] is a [[proportional representation]] voting method using [[Score Voting|5
Allocation is the default mechanism for achieving [[proportional representation]] in voting methods. Winners are selected in rounds. Each round elects the candidate with the highest total score. After each selection, the [[Hare quota]] of ballots which scored the winner the highest is allocated to
== Description ==
[[File:Proportional STAR Ballot - STAR-PR.png|alt=A sample STAR-PR ballot showing scores for each candidate ranging from 0 up to 5 stars. At the top of the ballot are voter instructions, and at the bottom a simple description of how votes are counted.|thumb|A sample STAR-PR ballot]]
Winners in Proportional STAR Voting (Allocated Score) are selected in rounds. Each round elects the candidate with the highest total score and then designates a quota's worth of voters from that candidate's strongest supporters as fully represented. Subsequent rounds include all voters who are not yet fully represented.
== Classification ==
Allocated Score is a [[
==Procedure==
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Each voter scores all candidates on a [0,5] scale
# Select the candidate with the highest sum of
# Set the ballot weight to zero for the [[quota]] of voters whose ballots contributed the highest scores to that winner.
#* If several voters have contributed the same score to the winner at the threshold of the quota then [[Fractional Surplus Handling]] is applied to those voters
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When multiple voters contributed the same score to the winner it may be the case that allocating them all to the winner would cause the quota to be exceeded but not allocating them all would cause the quota not to be met. For these voters on the cusp, an equal fraction of their ballot weight is allocated.
Fractional Surplus Handling ensures that voters who supported a candidate equally will be treated equally, while ensuring that the total weight of the ballots allocated for each winner will not exceed the Hare quota. It also preserves the [[Independence of irrelevant alternatives|Independence of Irrelevant Alternatives]] and [[Monotonicity]] criteria
Note that with Fractional Surplus Handling voters can have a fractional ballot weight and they can subsequently only contribute that fraction to the remaining candidates, both during subsequent score tabulation and allocation.
Warning: The sort must be done on the weighted score (not the original score from the ballots) or the mismatch between the selection and elimination will cause a free riding issue.
▲==Python Implementation==
Given a Pandas dataframe '''S''' with columns representing candidates and rows representing voters the entries would encode the score of all the ballots. For a max score of '''K''' and a desired number of winners '''W'''.
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Allocated Score is the natural extension of applying vote allocation to score ballots. While there are a number of variations on the theme that can be done, the Allocated Score method is the simplest which delivers great results. Beginning in 2018, The Equal Vote 0-5 Star Proportional Representation Research Committee spent two years comparing and studying the options at each stage in the tabulation process and ultimately, thanks to the work of Parker Friedland, [[Keith Edmonds]], [[Jameson Quinn]], [[Sara Wolk]], and a number of others, found Allocated Score to be the committee's consensus method, balancing competing considerations while meeting core criteria.
== References ==
[[Category:Cardinal voting methods]]
[[Category:Proportional voting methods]]
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