Search results
Results From The WOW.Com Content Network
Gibbard's theorem can be proven using Arrow's impossibility theorem. [citation needed] Gibbard's theorem is itself generalized by Gibbard's 1978 theorem [3] and Hylland's theorem, [4] which extend these results to non-deterministic processes, i.e. where the outcome may not only depend on the agents' actions but may also involve an element of ...
Gibbard's proof of the theorem is more general and covers processes of collective decision that may not be ordinal, such as cardinal voting. [note 1] Gibbard's 1978 theorem and Hylland's theorem are even more general and extend these results to non-deterministic processes, where the outcome may depend partly on chance; the Duggan–Schwartz ...
Gibbard's theorem provides limitations on the ability of any voting rule to elicit honest preferences from voters, showing that no voting rule is strategyproof (i.e. does not depend on other voters' preferences) for elections with 3 or more outcomes. The Gibbard–Satterthwaite theorem proves a stronger result for ranked-choice voting systems ...
The revelation principle shows that, while Gibbard's theorem proves it is impossible to design a system that will always be fully invulnerable to strategy (if we do not know how players will behave), it is possible to design a system that encourages honesty given a solution concept (if the corresponding equilibrium is unique). [3] [4]
On a rated ballot, the voter may rate each choice independently. An approval voting ballot does not require ranking or exclusivity. 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.
Download as PDF; Printable version; In other projects ... Cardinal voting. Score voting; ... Gibbard's theorem; Positive results.
Gibbard's theorem shows that any strategyproof game form (i.e. one with a dominant strategy) with more than two outcomes is dictatorial. The Gibbard–Satterthwaite theorem is a special case showing that no deterministic voting system can be fully invulnerable to strategic voting in all circumstances, regardless of how others vote.
According to Gibbard's theorem tactical voting is possible in all non-dictatorial deterministic voting systems that choose a single winner, and the Duggan-Schwartz theorem shows that most ranked methods electing multiple winners also fail to be strategyproof. A number of methods of tactical or strategic voting exist that can be used in ...