This paper presents a theoretical model that explains how decision rules and communication jointly affect collective outcomes in a small community under epistemic uncertainty. To see the likelihood of social reform and the probability of sensible decision-making under uncertainty, we compare two types of decision rules: unanimity rule and majority rule with veto. Also, we analyze the role of communication among voters before the voting occurs. We show that there exist equilibria and that once each player's preference is determined, the equilibrium behavior is specified. In addition, we use simulation methods to examine how the precision of group decision and the voters' welfare vary. [ABSTRACT FROM AUTHOR]