  We study a problem where a group of agents has to decide how a joint reward
should be shared among them. We focus on settings where the share that each
agent receives depends on the subjective opinions of its peers concerning that
agent's contribution to the group. To this end, we introduce a mechanism to
elicit and aggregate subjective opinions as well as for determining agents'
shares. The intuition behind the proposed mechanism is that each agent who
believes that the others are telling the truth has its expected share maximized
to the extent that it is well-evaluated by its peers and that it is truthfully
reporting its opinions. Under the assumptions that agents are Bayesian
decision-makers and that the underlying population is sufficiently large, we
show that our mechanism is incentive-compatible, budget-balanced, and
tractable. We also present strategies to make this mechanism individually
rational and fair.
