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Rated, evaluative,[1][2] graded,[1] or cardinal voting rules are a class of voting methods that allow voters to state how strongly they support a candidate,[3] by giving each one a grade on a separate scale.[1]
The distribution of ratings for each candidate—i.e. the percentage of voters who assign them a particular score—is called their merit profile.[4] For example, if candidates are graded on a 4-point scale, one candidate's merit profile may be 25% on every possible rating (1, 2, 3, and 4), while a perfect candidate would have a merit profile where 100% of voters assign them a score of 4.
Since rated methods allow the voters to express how strongly they support a candidate, these methods are not covered by Arrow's impossibility theorem,[5] and their resistance to the spoiler effect becomes a more complex matter. Some rated methods are immune to the spoiler effect when every voter rates the candidates on an absolute scale, but they are not when the voters' rating scales change based on the candidates who are running.[6]
- ^ a b c Baujard, Antoinette; Gavrel, Frédéric; Igersheim, Herrade; Laslier, Jean-François; Lebon, Isabelle (September 2017). "How voters use grade scales in evaluative voting" (PDF). European Journal of Political Economy. 55: 14–28. doi:10.1016/j.ejpoleco.2017.09.006. ISSN 0176-2680.
A key feature of evaluative voting is a form of independence: the voter can evaluate all the candidates in turn ... another feature of evaluative voting ... is that voters can express some degree of preference.
- ^ Darmann, Andreas; Grundner, Julia; Klamler, Christian (2019-09-01). "Evaluative voting or classical voting rules: Does it make a difference? Empirical evidence for consensus among voting rules". European Journal of Political Economy. 59: 345–353. doi:10.1016/j.ejpoleco.2019.04.003. ISSN 0176-2680.
- ^ "Ordinal Versus Cardinal Voting Rules: A Mechanism Design Approach".
- ^ de Swart, Harrie (2022-06-01). "How to Choose a President, Mayor, Chair: Balinski and Laraki Unpacked". The Mathematical Intelligencer. 44 (2): 99–107. doi:10.1007/s00283-021-10124-3. ISSN 1866-7414.
- ^ Vasiljev, Sergei (2008). "Cardinal Voting: The Way to Escape the Social Choice Impossibility". SSRN Electronic Journal. Elsevier BV. doi:10.2139/ssrn.1116545. ISSN 1556-5068.
- ^ Morreau, Michael (2014-10-13). "Arrow's Theorem". Stanford Encyclopedia of Philosophy. Retrieved 2024-10-09.
One important finding was that having cardinal utilities is not by itself enough to avoid an impossibility result. ... Intuitively speaking, to put information about preference strengths to good use it has to be possible to compare the strengths of different individuals' preferences.