The information simplicity of scoring rules

Voters assign a score to each of the many available alternatives. We study the normativeproperties of procedures that aggregate the scores collected in the ballot box. A vast class ofaggregation procedures, including procedures based on the pairwise comparison of alternatives,satisfy May''s famous conditions in our framework. We prove that, within such a plethora ofprocedures, scoring rules are singled out by a property related to their informational simplicity:in order to determine the winner, they do not take into account the specific distribution ofscores chosen by each voter. The result is shown to hold regardless of the introduction ofasymmetry among the alternatives.