Approval voting: Difference between revisions

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== Notes ==
Approval voting passes [[Favorite Betrayal]], so unlike [[Choose-one FPTP voting]], it never hurts a voter to support their favorite. Example where that makes a difference:
 
10 A>B
 
41 B>A
 
49 C>A
 
In FPTP, most A-top voters would likely support B instead, to avoid electing C. But with Approval, they can support both A and B, and if a few C-top voters support A as well, then A will win. This is also an example of averted [[Center squeeze effect|center squeeze effect]].
 
However, there is potential for what is known as the [[Chicken dilemma|chicken dilemma]], where one majority subtraction withholds support for the other subtraction to help its candidate win rather than the other subfaction's candidate.
 
Approval voting is also called set voting or unordered voting, because a voter expresses on their ballot the set of candidates that they prefer above all others, but is not allowed to rank (order) the candidates from 1st to 2nd to 3rd to... to last. In other words, it only allows voters to rank all candidates either 1st or last.
 
One of the major implications of Approval voting in relation to [[choose-one FPTP voting]] is that with Approval, there is no way to tell (solely with the vote totals for each candidate) whether a voter who supported one candidate did or didn't support another. For example, in FPTP (assuming no equal ranking was allowed, a la [[cumulative voting]]), if Obama gets 30 votes and Romney gets 20, then it is guaranteed that none of the 30 voters who supported Obama also supported Romney, and vice versa. But with Approval, it is possible (albeit unlikely in this example) that everyone who voted for Romney also voted for Obama, and that Obama really only has 10 voters who support him but not Romney. This means that proportional forms of Approval voting are not as precinct-summable as the proportional form of FPTP, [[SNTV]], because not only must one know how many voters approved each candidate to calculate the winner(s) in Approval PR methods, but also which candidates each ballot approved. With choose-one ballots, knowledge of the former yields knowledge of the latter.
 
The Approval voting winner is also always someone from the [[Smith set]] if voters' preferences truly are dichotomous (i.e. they don't have ranked preferences, but rather, honestly only support or oppose each candidate).
 
==See also==