Sophie Bade

More Strategies, More Nash Equilibria

This short paper isolates a non-trivial class of games for which there exists a monotone relation between the size of pure strategy spaces and the number of pure Nash equilibria (Theorem). This class is that of two- player nice games, i.e., games with compact real intervals as strategy spaces and continuous and strictly quasi-concave payoff functions, assumptions met by many economic models. We then show that the sufficient conditions for Theorem to hold are tight.

Electoral Competition with Uncertainty Averse Parties

The nonexistence of equilibria in models of electoral competition involving multiple issues is one of the more puzzling results in political economics. In this paper, we relax the standard assumption that parties act as expected utility maximizers. We show that equilibria often exist when parties with limited knowledge about the electorate are modeled as uncertainty-averse. What is more, these equilibria can be characterized as a straightforward generalization of the classical median voter result.

Randomization devices and the elicitation of ambiguity-averse preferences

In random incentive mechanisms agents choose from multiple problems and a randomization device selects a single problem to determine payment. Agents are assumed to act as if they faced each problem on its own. While this approach is valid when agents are expected utility maximizers, ambiguity-averse agents may use the randomization device to hedge and thereby contaminate the data.

Serial dictatorship: The unique optimal allocation rule when information is endogenous

The study of matching problems typically assumes that agents precisely know their preferences over the goods to be assigned. Within applied contexts, this assumption stands out as particularly counterfactual. Parents typically do invest a large amount of time and resources to find out which school would be best for their children, doctors run costly tests to establish which kidney might be best for a given patient. In this paper I introduce the assumption of endogenous information acquisition into otherwise standard house allocation problems. I find that there is a unique ex ante Pareto-optimal, strategy-proof and non-bossy allocation mechanism: serial dictatorship. This stands in sharp contrast to the very large set of such mechanisms for house allocation problems without endogenous information acquisition.

Fairness and group-strategyproofness clash in assignment problems

No group-strategyproof and ex-post Pareto optimal random matching mechanism treats equals equally. Every mechanism that arises out of the randomization over a set of non-bossy and strategyproof mechanisms is non-bossy. Random serial dictatorship, which arises out of a randomization over all deterministic serial dictatorships is non-bossy but not group-strategyproof.

Pareto-optimal assignments by hierarchical exchange

Papai’s 2000 hierarchical exchange mechanisms for house allocation problems determine matchings as the outcome of multiple rounds of trading cycles. Any hierarchical exchange mechanism can be defined through a structure of ownership, which determines the ownership of houses after any round of trading cycles. Given a permutation of agents, a “permuted” hierarchical exchange mechanism can be constructed by consistently permuting agents over the entire structure of ownership. The paper shows that for any Pareto-efficient matching and any hierarchical exchange mechanism, there is a permutation of agents in the ownership structure such that the induced permuted hierarchical exchange mechanism leads to this matching.

Matching Allocation Problems with Endogenous Information Acquisition

The paper introduces the assumption of costly information acquisition to the theory of mechanism design for matching allocation problems. It is shown that the assumption of endogenous information acquisition greatly changes some of the cherished results in that theory: in particular, the first-best might not be implementable. Moreover, it might not even be possible to implement the second-best through trade. In addition, the paper highlights the use of randomness in setting incentives for efficient learning. The trade-offs among simultaneous and sequential learning and among efficient learning and efficient allocations are discussed.

Does Political Representation through Parties Decrease Voters' Acceptance of Decisions?

Are decisions by political parties more or less accepted than direct-democratic decisions? The literature on parties as brand names or labels suggests that the existence of political parties lowers information and transaction costs of voters by providing ideological packages. Building on this important argument, we posit that this informational rationale for parties is not universally applicable and is contingent on the context of the decision that is made. Intermediary political decision-making institutions may impose additional costs on voters in situations where the decision is perceived to be personally important to the individual voter. We conduct an experimental online vignette study to substantiate these claims. The results imply that a combination of representative democracy and direct democracy, conditional on the distribution of issue importance among the electorate, is optimal with regard to acceptance of a decision.

Ambiguity Aversion in Models of Political Economy

Four papers that use ambiguity aversion in political economy are reviewed. The first two (Bade, 2011a and 2011b) find that two important puzzles (equilibrium existence with multidimensional issue spaces and platform convergence) of the Downs-Hotelling model of electoral competition can be addressed by modeling parties as ambiguity-averse. The second two papers pertain to the Condorcet model of information aggregation. Ghirardato and Katz (2006) explains selective abstention through ambiguity aversion. Ellis (2012) shows that this abstention motive can be strong enough to prevent any information aggregation.