Pareto efficiency: Difference between revisions

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The '''Pareto criterion''' is a basic criterion for evaluating [[voting system|voting systems]]. It can be defined in this way:
The '''Pareto criterion''' is a basic criterion for evaluating [[voting system|voting systems]]. It can be defined in this way:


:''If every voter ranks candidate ''A'' above candidate ''B'', then ''B'' must not be elected''.
{{definition|If every voter ranks candidate ''A'' above candidate ''B'', then ''B'' must not be elected.}}


This criterion is important in the context of [[Arrow's impossibility theorem]].
This criterion is important in the context of [[Arrow's impossibility theorem]].

Revision as of 02:43, 22 October 2019

The Pareto criterion is a basic criterion for evaluating voting systems. It can be defined in this way:

If every voter ranks candidate A above candidate B, then B must not be elected.

This criterion is important in the context of Arrow's impossibility theorem.

Virtually every devised election method satisfies this criterion. An example of a method which would fail it would be Random Candidate, where some candidate is elected at random, regardless of the submitted votes.