Strategyproof Judgment Aggregation under Partial Information

We introduce a model of judgment aggregation in which individuals do not necessarily have full information regarding the judgments held by their peers. This intuitively limits an individual’s ability to strategically manipulate the aggregation process. Our results confirm this basic intuition. Specifically, we show that known impossibility results concerning the existence of reasonable strategyproof judgment aggregation rules break down once we abandon the classical assumption of full information. For instance, the simple plurality rule is strategyproof in case individuals do not have any information about their peers, while the well-known premise-based rule can be rendered strategyproof by withholding only a negligible amount of information.