| Abstract: | A social planner selects heterogeneously biased experts to (either sequentially or simultaneously) acquire costly signals, and then agents vote between two alternatives. To maximize social welfare, the social planner adopts an alternating mechanism—choosing extremely biased experts whose preferences oppose the pivotal voter's current preference—in the optimal sequential mechanism, whereas she chooses mildly biased experts in the optimal simultaneous mechanism. Despite the flexibility of a sequential mechanism, the optimal simultaneous mechanism can achieve strictly higher social welfare when information cost is low. Supermajority rules can dominate simple majority rule in terms of both information acquisition and social welfare. |
