Difference between revisions of "Ballot"
Jump to navigation Jump to search
A '''ballot''' is a voter's expression of preference among the candidates. There are four main ways to do this in the context of voting methods:
▲- [[Approval ballot|Approval ballots]] (mark all the candidates that you support),
▲- [[Ranked ballot|ranked ballots]] (rank the candidates in order of preference: 1st, 2nd, 3rd, etc. Some ranked ballots allow a voter to give multiple candidates the same rank to indicate no preference between those candidates.) and
▲- [[Ratings ballot|rated ballots]] (you rate the candidates on a scale, generally starting from 0, going up to any value, often 5 or 10. Usually only certain in-between values are allowed i.e. if the scale is from 0 to 10, it usually isn't allowed for someone to give a rating of, say, 9.35).
There are several intersections between the various ballot types. For example, the information contained on an Approval ballot can also be found from a ranked or rated ballot if an [[Approval threshold|approval threshold]] is utilized, and in fact, an [[Approval voting#Ballot types|Approval ballot]] is itself a type of rated ballot where the only allowed ratings are "disapprove" and "approve" (0 and 1). A choose-one ballot is itself an Approval ballot with the restriction of only marking one candidate, and can also be thought of as a ranked or rated ballot where only the candidate(s) ranked 1st/rated highest are treated as supported. A ranked ballot can be (at least partially) reconstructed from any of the other three ballot types i.e. if a voter scored one candidate higher than another (or marked one candidate but not another), then it is known for certain that that voter would also rank that candidate higher than the other.
(Is equivalent to a choose-one ballot when only one candidate can be approved).
|Yes (one of the candidates ranked 1st would be marked on a choose-one ballot)
|Only if an approval threshold is used (or if the voter ranked every candidate either 1st or last; it must also be assumed the voter would approve anyone they ranked 1st).
|Only if the voter ranked every candidate 1st or last.
(Is equivalent to an approval ballot when only two ratings are allowed.)
|Yes (though with a slight caveat: only to the extent that enough scores were allowed i.e. if there are 7 candidates, and the voter has a preference between each of them, but was only allowed to give each of them one of 6 scores, then by pigeonhole principle they would've had to lie and indicate an equal preference between at least 2 of them, so the reconstructed ranking won't be perfectly accurate).
(The intersection between ballot types indicates relations. For example, the cell in the third row and fourth column indicates whether approval ballots give the information required to reconstruct a ranked ballot and with how much reliability).
This table shows that generally speaking, a rated ballot without an approval threshold provides the most information of any ballot type without an approval threshold, and that a rated ballot with an approval threshold provides the most information of any ballot type.As an example of all four ballot types, suppose there are five candidates to consider: Alicia, Brandon, Charlie, David, and Eileen.
Choose-one and Approval ballots are often shown as some form of:<blockquote>Alicia[X] Brandon Charlie David Eileen[X]</blockquote>meaning "Alicia and Eileen are supported by this voter"<blockquote>or Alicia>Eileen=(approval threshold)>Brandon=Charlie=David</blockquote>meaning "Alicia is my 1st choice, Eileen is my 2nd choice, I approve everyone who is my 2rd choice or higher, and all the other candidates are worse than my 2nd choice"
Ranked ballots are often shown as:<blockquote>Alicia>Eileen>Brandon=Charlie=David</blockquote>meaning "Alicia is better than Eileen, Eileen is better than any of (Brandon, Charlie, David) and Alicia is also better than any of (Brandon, Charlie, David)" or
A '''ratings ballot''', or '''cardinal ballot''', is a ballot in which, for each candidate, a voter is asked to "rate" the candidate on a scale, for example from 0 to 100 or from
An [[approval ballot]] can be thought of as a ratings ballot with an integer scale from 0 to 1 (inclusive).
* [[Anti-plurality voting]]
== External links
* Declaration of Election-Method Reform Advocates: Ban Single-Mark Ballots