# Pareto criterion

From Electowiki

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.