Manipulability of majoritarian rules by coalitions with the same first-ranked alternative

Abstract The coalitional manipulability of 13 majoritarian aggregation schemes (voting rules) is studied by computational experiments. We consider a special case of coalition formation in which all agents of manipulating coalition report the same first-ranked alternative upon manipulation, i.e. a group of agents misrepresents their preferences and they agree that the same alternative will be on the first place of their insincere preferences. We find out that in most cases one of the least manipulable rules in this framework is Minimal Dominant Set, which was not among the least manipulable rules in the case of individual manipulation.

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