# Anne-Katrin Roesler

Associate Professor

University of Toronto, Department of Economics

Research interests: Mechanism Design, especially Information Design, Information Economics, Game Theory.

### Published, accepted, and forthcoming papers:

Multi-Dimensional Screening: Buyer-Optimal Learning and Informational Robustness (joint with Rahul Deb) [pdf]

Review of Economic Studies, 2024, Volume 91, Issue 5, 2744-2770

A monopolist seller of multiple goods screens a buyer whose type is initially unknown to both but drawn from a commonly known distribution. The seller chooses a mechanism to maximize her worst-case profits against all possible signals from which the buyer can learn about his values for the goods. We show that it is robustly optimal for the seller to bundle goods with identical demands (these are goods that can be permuted without changing the buyer's prior type distribution). Consequently, pure bundling is robustly optimal for exchangeable prior distributions. For exchangeable priors, pure bundling is also optimal for the seller in the information environment (with the reverse timing) where an information designer, with the objective of maximizing consumer surplus, first selects a signal for the buyer, and then the seller chooses an optimal mechanism in response. We derive a formal relationship between the seller's problem in both information environments.

Learning Before Trading: On The Inefficiency of Ignoring Free Information (joint with Doron Ravid and Balázs Szentes) [pdf]

Journal of Political Economy, 2022, 130:2, 346-387

This paper analyzes a bilateral trade model where the buyer's valuation for the object is uncertain and she can privately purchase any signal about her valuation. The seller makes a take-it-or-leave-it offer to the buyer. The cost of a signal is smooth and increasing in informativeness. We characterize the set of equilibria when learning is free and show that they are strongly Pareto ranked. Our main result is that, when learning is costly but the cost of information goes to zero, equilibria converge to the worst free-learning equilibrium.

Buyer-Optimal Learning and Monopoly Pricing (joint with Balázs Szentes) [pdf] - (Supplemental Material, pdf)

American Economic Review, 2017, 107(7), 2072-2080

This paper analyzes a bilateral trade model where the buyer's valuation for the object is uncertain and she observes only a signal about her valuation. The seller gives a take-it-or-leave-it offer to the buyer. Our goal is to characterize those signal structures which maximize the buyer's expected payoff. We identify a buyer-optimal signal structure which generates (i) efficient trade and (ii) a unit-elastic demand. Furthermore, we show that every other buyer-optimal signal structure yields the same outcome as the one we identify, in particular the same price.

### Working Papers:

How Informed Do You Want Your Principal to Be? (joint with Rahul Deb and Mallesh Pai) [pdf] (new)

We study a bilateral trade setting with interdependent values and two-sided private information. A buyer’s value for a good depends both on his privately known type and the good’s quality that he does not observe. The cost of the seller also depends on both the buyer’s type and the quality; she learns about the latter via a private signal whose realization is the seller’s private information. How much (if any) private information would the buyer want the seller to have? We answer this question by characterizing the buyer-optimal outcome: this is the information structure and the corresponding seller-optimal equilibrium of the informed principal game that yield the highest consumer surplus. We show that, and characterize precisely when, private information for the seller leads to higher consumer surplus relative to an uninformed seller. Under these conditions, the information structure in the buyer-optimal outcome is typically noisy.

Committee Composition: The Impact of Diversity and Partisanship on Voting Behavior [pdf] (updated)

We propose and analyze a committee voting model in which players with interdependent values take binary decisions. Each player holds two-dimensional private information: a private signal about the payoff state, and a private preference type that captures their level of partisanship. We show that, in equilibrium, committee members adopt cutoff strategies that are monotone in preference types. We identify a committee's composition, captured by the distribution of private preference types, impacts its decisions. As committee members are drawn from increasingly partisan populations, equilibrium cutoffs move away from the sincere voting threshold. Conversely, when committee members originate from more diverse populations, equilibrium cutoffs move closer to the sincere voting threshold. We discuss implications for the set of alternatives that different committees accept.

Private Learning and Exit Decisions in Collaboration (joint with Yingni Guo) [pdf]

We study a continuous-time collaboration model in which two players participate in a joint project. At any time, players decide between exerting effort or exiting (irreversible) to secure the outside option's payoff. The arrival rate of a public success is proportional to players' efforts, depends on the binary state, and is positive in both. A player's effort is also an investment in private learning: They may privately learn that the state is bad, in which case exerting effort is inefficient.

We identify an equilibrium with three phases. Uninformed players consitently exert effort, while those informed about the project being bad stop exerting effort. In the first, no-exit phase, informed players do not exit. In the subsequent, gradual-exit phase, they exit at a finite rate. They exit immediately in the final phase. We find that, despite becoming more pessimistic over time, players may increase their effort in the no-exit phase. Moreover, endogenous deadlines can exist. The equilibrium exhibits two inefficiencies: delayed effort and information transmission. Increasing the outside option's payoff mitigates both inefficiencies and fosters collaboration.

Information Disclosure in Markets: Auctions, Contests and Matching Markets [pdf]

We study the impact of information disclosure on equilibrium properties in a general model of a two-sided matching market that incorporates a large class of market design environments. In this model, each agent first privately observes an informative, but potentially noisy, signal about his private type. The agents then enter a matching stage in which they choose signaling investments to compete for match partners. In order to study the impact of information disclosure, we introduce a criterion that orders signals in terms of their informativeness. We show that information disclosure increases the expected total match output but may also increase wasteful signaling investments due to amplified competition within groups. The second effect may dominate, leading to a decrease in expected welfare. Disclosure effects on equilibrium properties depend on whether information is disclosed to agents on the short or the long side of the market. Implications of our findings to auctions, contests and matching markets are discussed.

Mechanism Design with Endogenous Information [pdf]

In mechanism design problems with endogenous information, regularity properties of the distribution of posterior estimates (types) are essential for tractability. Important properties are a monotone hazard rate, increasing virtual valuations or costs. Difficulties arise since these properties are not preserved under mixtures, and regularity of the prior distribution may not translate to the distribution of posterior types. In this note, we identify sufficient conditions on the primitives of an information structure, which guarantee that the distribution of posterior types has a monotone hazard rate, increasing virtual valuations or costs. These characterization results make it possible to study mechanism design problems with endogenous information, without imposing regularity conditions on the interim stage or restricting attention to specific information structures. Applications to information acquisition and disclosure in optimal auctions, and to allocation problems without money are discussed.

### Other Contributions:

Advances in Mechanism Design: Information Management and Information Design [pdf]

The Bonn Journal of Economics, Volume V, No. 1, July 2016, pp. 13 - 24.