Information Aggregation in Elections
Saturday, Jan. 6, 2018 10:15 AM - 12:15 PM
- Chair: Marco Battaglini, Cornell University
Full Information Equivalence in Large Elections
AbstractWe study the problem of aggregation of private information in common value elections with two or more alternatives and with general state and signal spaces. We provide general conditions on the environment ensuring existence of a sequence of equilibria of the voting game that eciently aggregates information as the population size grows to innity. The conditions explore the geometry of partitions on the distributions over private signals induced by the common state-dependent utility of the voters. Such conditions are met generically when the signal space is rich enough relative to the state space, and fail
robustly when the state space is rich relative to the signal space.
Costly Advice, Protests and Nonbinding Voting
AbstractWe study a scenario in which a receiver is collecting non-binding advice for a binary decision from partially informed senders who can send binary messages. This reflects situations such as non-binding voting of shareholders on a management proposal, protests by citizens, and polls. Under complete information, the preferences of the receiver and the senders are aligned but there is a conflict of interest over the trade-off of Type I and Type II errors. Existing work shows that for many such situations, the bias prohibits the transmission of any information. Here, in contrast to this work, we consider a setting in which one of the messages is costly. For example, there are positive costs of voting but no costs of abstention. We show that responsive equilibrium which transmits informative advice exists. When there are many senders, with costly advice, the outcome is equivalent to the one under complete information. In our general model, we also allow for noise induced by other motives. With noise, participation in an election becomes a strategic complement, with citizens joining voices to overcome the noise and make their opinion heard. Thus, receiver obtains some useful information but not all information. Even when the population size is arbitrarily large information partially aggregates leading to indeterminacy in receiver's decisions.
Modes of Persuasion Toward Unanimous Consent
AbstractA fully committed sender seeks to sway a collective adoption decision by multiple voters with correlated payoff states and heterogeneous thresh- olds of doubt through designing experiments. We characterize the sender- optimal policy under unanimity rule for two main persuasion modes. Under general persuasion, the sender makes the most demanding voters indifferent between decisions, while the more lenient voters strictly benefit from per- suasion. Under individual persuasion, the sender designates a subgroup of rubber-stampers, another of perfectly informed voters, and a third of par- tially informed voters. The most demanding voters are strategically accorded high-quality information. In contrast, under nonunanimous rules, general persuasion guarantees a sure adoption, while individual persuasion does not; voters prefer the latter due to the partial check they have on adoption.
- D7 - Analysis of Collective Decision-Making