Abstract
We develop a model for the aggregation of preferences that do not need to be either complete or
transitive. Our focus is on the normative characterisation of aggregation rules under which each agent
has a weight that depends only on the size of her
ballot, i.e., on the number of pairs of alternatives for
which she chooses to report a relative ranking. We
show that for rules that satisfy a restricted form of
majoritarianism these weights in fact must be constant, while for rules that are invariant under agents
with compatible preferences forming pre-election
pacts it must be the case that an agent’s weight is
inversely proportional to the size of her ballot