Electoral system: Difference between revisions
Removed "Broadness criterion" which isn't defined anywhere, and removed some rarely used acronyms too
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{{Wikipedia|Electoral system}}
An '''electoral system''' (also referred to as an '''election method''', '''voting system''', '''voting rule''', '''voting scheme''', etc.) is a system for groups of people to select one or more options from many, taking into account the individual preferences of the group members, or more generally to find society's preference among all the candidates (1st place, 2nd place, etc.). Voting is often seen as the defining feature of democracy, and is best known for its use in public elections — but it can also be used to award prizes, to select between different plans of action, or as a means for computer programs to evaluate which solution is best for a complex problem. ▼
A key property of electoral systems is that, because they are algorithms, they must be formally defined. For example, [[consensus]] is sometimes put forward as a voting system. But consensus is a broad way of working with others, analogous to democracy or anarchy.▼
Most of voting theory can be thought of as deciding the [[Number of supportable candidates in various voting methods|Number of supportable candidates in the voting method]], who should win when there isn't a clearly best candidate, and deciding whether elements of [[proportional representation]] are desirable. ▼
An '''electoral system''' (also referred to as an '''election method''' or '''voting system''') is a system for groups of people to select one or more options from many, taking into account the individual preferences of the group members, or more generally to find society's preference among all the candidates (1st place, 2nd place, etc.). Voting is often seen as the defining feature of democracy, and is best known for its use in public elections — but it can also be used to award prizes, to select between different plans of action, or as a means for computer programs to evaluate which solution is best for a complex problem.
Also see the [[voting theory glossary]]. [[Vote counting]] explains how the ballots submitted by the voters can be physically turned into the information needed to compute the result of a voting method. ▼
See '''[[:Category:Electoral systems]]''' for the category associated with this article. This category on electowiki corresponds to "electoral systems" category on [[English Wikipedia]] (found here: "[[wikipedia:Category:Electoral systems]]").
[[Category:Electoral systems]]
== Summary ==
:''main category: [[:Category:Electoral systems|Category:Electoral systems]]''
[[File:Voting system Euler diagram.svg|thumb|Several of the popular voting methods, categorized by their important properties]]
▲An '''electoral system''' (also referred to as an '''election method''', '''voting system''', '''voting rule''', '''voting scheme''', etc.) is a system for groups of people to select one or more options from many, taking into account the individual preferences of the group members, or more generally to find society's preference among all the candidates (1st place, 2nd place, etc.). Voting is often seen as the defining feature of democracy, and is best known for its use in public elections — but it can also be used to award prizes, to select between different plans of action, or as a means for computer programs to evaluate which solution is best for a complex problem.
▲A key property of electoral systems is that, because they are algorithms, they must be formally defined. For example, [[consensus]] is sometimes put forward as a voting system. But consensus is a broad way of working with others, analogous to democracy or anarchy.
▲:''main category: [[:Category:Voting methods]]''
▲Most of voting theory can be thought of as deciding the [[Number of supportable candidates in various voting methods|Number of supportable candidates in the voting method]], who should win when there isn't a clearly best candidate, and deciding whether elements of [[proportional representation]] are desirable.
▲Also see the [[voting theory glossary]]. [[Vote counting]] explains how the ballots submitted by the voters can be physically turned into the information needed to compute the result of a voting method.
Voting methods can generally be categorized into rated and ranked methods. [[Rated method|Rated methods]] look for a candidate who is most "satisfying" to voters (based on their ratings of the candidates), i.e. [[Score voting]]. Most [[Ranked method|ranked methods]] try to extend [[majority rule]] to situations where there are more than two candidates. [[IRV|IRV/RCV]] and [[:Category:Condorcet methods|Condorcet methods]] are the most notable of these.
=== Criteria in evaluating electoral systems ===
Various [[:Category:voting system criteria|criteria]] are used in evaluating voting systems. However, it is impossible for one voting system to pass all criteria in common use. For example, [[Arrow's impossibility theorem]] demonstrates that many desirable criteria are mutually inconsistent.
===Determinism and delegation===
In addition, there are some distinctions between deterministic and non-deterministic voting methods (deterministic means the voting method always gives the same results when the same ballots are inputted; non-deterministic usually means there's some kind of randomness to the voting method. Most likely you're looking for deterministic methods), and delegated and non-delegated methods (delegated methods allow/force voters to give up their voting power to someone else who decides who wins. You're probably looking for non-delegated methods).
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See [[ballot]].
Different voting systems have different forms for allowing the individual to express their [[tolerances versus preferences|tolerances or preferences]]. In [[ranked ballot]] or "preference" voting systems, like [[instant-runoff voting]], the [[Borda count]], the Modified Borda count MBC or a [[Condorcet method]], voters order the list of options from most to least preferred. In [[range voting]], voters rate each option separately. In [[first-past-the-post]] (also known as plurality voting), voters select only one option, while in [[approval voting]], they can select as many as they want. In voting systems that allow [[plumping]], like [[cumulative voting]], voters may vote for the same candidate multiple times.
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* The voting system should always give a result
*Removing a candidate should not change the winner of an election unless that candidate is the winner ([[independence of irrelevant alternatives]])
*Non-dictatorship (i.e. more than one person's vote matters)
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*[[Proportional representation|Proportionality]]
*Simplicity — both for the voters, and for the people counting the votes
*Resistance to [[Tactical voting]]
*Resistance to [[Vote splitting]]
*Reduction of potential for dispute after the fact
*Reduction of potential for fraud
*[[Monotonicity criterion]]
*[[Consistency Criterion]]
*[[
*[[Generalized Condorcet
*[[Strategy-Free criterion]] (SFC)
*[[Generalized Strategy-Free criterion]] (GSFC)
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*[[Weak Defensive Strategy criterion]] (WDSC)
*[[Favorite Betrayal criterion]] (FBC)
*[[Participation criterion]]
*[[Summability criterion]]
=== Utility ===
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****[[Schulze method|Schulze]], which is also known as "Beatpath Method" or "Cloneproof Schwartz Sequential Dropping"
****[[Copeland's method]]
****Dodgson-Hare [https://jamesgreenarmytage.com/dodgson.pdf] Under some assumptions very resistant to strategies
***[[Bucklin voting]]: approval with virtual runoff; each voters' ballot is counted for more candidates each round until some candidate reaches a majority
*[[Cardinal Voting]]: voting A valid vote allows independent numerical values to be associated with each candidate. (The set of valid values is limited. So it's usually voting on a scale of, say, 0 to 5)
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*[http://www.mcs.vuw.ac.nz/~ncj/comp303/schulze.pdf A New Monotonic and Clone-Independent Single-Winner Election Method] ('''[[Portable Document Format|PDF]]''') by Markus Schulze ([http://www.citizensassembly.bc.ca/resources/submissions/csharman-10_0409201706-143.pdf mirror1], [http://lists.gnu.org/archive/html/demexp-dev/2003-09/pdflQW7IlpAfC.pdf mirror2])
*[http://www.masquilier.org/republic/election/ A different way to vote] by AugustinMa. Of interest is the [http://www.masquilier.org/libre/phpbb/ modified] version of the popular phpBB bulletin board that can be found [http://www.masquilier.org/agora/ here]. The board allows the users to create plurality, approval and Condorcet ([[Schulze method|Schulze]]) polls and [http://www.masquilier.org/agora/viewforum.php?f=7 cast their ballots].
=== Auto-generated list ===
{{Special:CategoryTree/Voting_system_criteria}}
== See also ==
*[[:Category:Voting theory|Category:Voting theory]]
*[[:Category:Electoral systems|Category:Electoral systems]]
{{fromwikipedia}}
[[Category:Electoral systems|*]]
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