Anonymity (social choice)

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In social choice theory, a function satisfies voter anonymity, neutrality, or symmetry if the rule does not discriminate between different voters ahead of time; in other words, it does not matter who casts which vote. Formally, this is defined as saying the rule returns the same outcome (whatever this outcome may be) if the vector of votes is permuted arbitrarily.^[1][2]

Similarly, candidate anonymity (neutrality, symmetry) says that the rule does not discriminate between different candidates ahead of time. Formally, if the labels assigned to each candidate are permuted arbitrarily, the returned result is permuted in the same way.^[1][2]

Some authors reserve the term anonymity for voter symmetry and neutrality for candidate symmetry,^[1][2] but this pattern is not perfectly consistent.^[3]: 75