Cardinal proportional representation: Difference between revisions

Add Peters et al paper
(Refactor PSC comparison and do minor name cleanup)
(Add Peters et al paper)
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Also see the following section for some categories.
 
When investigating cardinal PR, it is often categorized into optimal PR methods, which generally work by assigning every possible [[winner set]] a score based on how good it is, and picking the best winner set out of all possible winner sets, and sequential PR methods, which elect one candidate at a time. Optimal PR has the issue of being non-hand-countable and very computationally expensive and complex (in fact, with large committees, they may be both completely impossible to compute and very, very vulnerable to strategic voting<ref>{{Cite web|url=https://www.rangevoting.org/QualityMulti.html|title="Optimal proportional representation" multiwinner voting systems I: methods, algorithms, advantages, and inherent flaws|last=Smith|first=Warren D.|date=October 2015-10|website=rangevoting.org|url-status=live|archive-url=|archive-date=|access-date=}}</ref>), so in practice, many sequential cardinal PR methods are designed to approximate certain optimal PR methods. When simulating the quality of various cardinal PR methods, sometimes it's common to use optimal PR methods more as "benchmarks" of how good the winner set chosen by the sequential method is, rather than as an actual way of running an election.
 
The [[KP transform]] can be very useful in allowing '''Approval PR''' methods ([[Approval voting]]-based cardinal PR methods) to work with rated ballots with more than two allowed scores.
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The trouble with this is, politicians are not like tap water and oranges. That reasoning would make sense if politicians were “wholly owned” by the Blues, just as Peter wholly-eats an apple. But even the most partisan politicians in Canada do a lot of work to help Joe Average constituent whose political leanings they do not even know. At least, so I am told.
 
===Incompatibility of the philosophies===
 
Pick your poison: it seems that all proportional voting methods must fail one of two closely related properties:
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Phragmen/Monroe-type methods fail 1. and Thiele-type methods fail 2. and as of this point, it doesn’t seem possible to have them both without giving up PR.
 
Peters and Skowron determined other properties that Phragmén passes but no Thiele-type method can pass, further indicating an incompatibility between the Phragmén and Theile philosophies.<ref name="Peters Skowron 2019">{{cite arXiv | last=Peters | first=Dominik | last2=Skowron | first2=Piotr | title=Proportionality and the Limits of Welfarism | date=2019-11-26 | eprint=1911.11747 | class=cs.GT}}</ref>
 
== Notes ==
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