Electoral systems

This category is for articles about voting methods. Articles about specific voting methods should be moved into sub-categories that describe their properties.

Electoral systems

main article: Electoral system a.k.a. "Voting system"

An electoral system (also referred to as a voting system or election method) 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 whether and how voters should be allowed to express their preference on more than one candidate, who should win when there isn't a clearly best candidate, and deciding whether elements of proportional representation are desirable.

Several of the popular voting methods, categorized by their important properties

Voting methods can generally be categorized into rated and ranked methods. 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 methods try to extend majority rule to situations where there are more than two candidates. IRV/RCV and Condorcet methods are the most notable of these.

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).

It's also worth looking at what type of ballot the voting method uses i.e. if it uses an Approval ballot (voters can either support or oppose each candidate, like rating them thumbs up or down), a ranked ballot (voter ranks candidates 1st, 2nd, 3rd, etc.), etc.

Criteria in evaluating voting systems

Various 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.

See also

• Voting theory

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