Joey Feffer

Joey Feffer
PhD Student, Economic Analysis & Policy
PhD Program Office Graduate School of Business Stanford University 655 Knight Way Stanford, CA 94305

Joey Feffer

Welcome to my page! I'm a 6th-year PhD Candidate at Stanford GSB. My work is in microeconomic theory, with a focus on robustness and simplicity in various mechanism design settings. Please visit my personal webpage for up-to-date information!

I am on the 2026-27 academic job market.

Research Interests

  • Microeconomic Theory
  • Market Design

Job Market Paper

Optimal Auctions For Additive Goods: A Geometric Approach
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I study the revenue-maximizing sale of multiple symmetric goods to multiple symmetric bidders, both in an unrestricted Bayesian setting and under simplicity requirements. Using a geometric representation of allocation rules, I characterize the designer’s screening incentives in the unrestricted setting and identify a regularity condition under which global incentive constraints can be relaxed and optimal allocations are guided by endogenous virtual values. I then introduce a novel class of auctions called linked clock auctions, which allow for coarse forms of multidimensional screening while maintaining dimensions of strategic simplicity. I show that optimal linked clock auctions allocate according to coarse virtual values derived from the model’s primitives. These virtual values are coarsenings of the endogenous virtual values of the unrestricted setting, making precise how strategic simplicity restricts screening. Simulations show that optimal linked clock auctions achieve more than 99% of the estimated unrestricted optimal revenue in one benchmark setting and outperform separate selling by more than 20% in others.

Working Papers

Compound Proportional Auctions
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(with Ben Brooks and Songzi Du) We consider the design of optimal auctions when buyers may have asymmetric and/or interdependent values. All that is known to the seller is each buyer’s ex ante expected value and an upper bound on the values. We describe a new class of mechanisms which we term compound proportional auctions: Each buyer submits a bid, which is a non-negative real number. The auction then clears in a series of rounds. Within each round, a proportional auction (Brooks and Du, 2021) is run allocate the remaining supply that is left over from previous rounds, among a set of active buyers. At the end of the round, those active buyers with the lowest expected value become inactive. Our main result is that compound proportional auctions maximize the revenue guarantee: minimum expected revenue across all information structures and Bayes-Nash equilibria.

Strategically Analogous Mechanisms
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(with Filip Tokarski) This paper studies when strategic understanding acquired in one mechanism can be transferred to another. We introduce a framework in which agents’ knowledge is represented as a set of payoff comparisons they can make, and use it to formalize what it means to understand that a strategy profile is an equilibrium. We first apply this framework to mechanisms that are strategically equivalent—that is, share the same game form up to relabeling of actions—and show that agents’ understanding of equilibrium transfers across such mechanisms once the relevant action correspondences are explained to them. We then define strategic analogy, a weaker notion that allows not only actions but also types to be remapped, and show that understanding of equilibrium transfers across strategically analogous mechanisms once agents recognize how actions and types correspond. Applications include single- item auctions, scoring auctions, and nonlinear pricing with capacity constraints.

Belief Precision and Simplicity in Scoring Auctions
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I develop a simplicity criterion for mechanism design, based on belief precision, the number of moments of a type distribution required to compute equilibrium strategies. Focusing on a class of multidimensional procurement auctions called first-score auctions, I show a sharp dichotomy: these mechanisms either have belief precision of two or require full distributional knowledge. This distinction is governed by whether the auction satisfies the fixed-order property, which ensures that the ex post allocation ranking of types is invariant across distributions. I then provide a simple, equilibrium-free test to determine whether a first-score auction has belief precision two. Finally, I microfound the concept by introducing a prior-free game with information acquisition: when agents learn from realistic signal structures about their opponents’ types, first-score auctions with low belief precision are exactly those that admit robust equilibria. The results offer a framework to compare mechanisms along a dimension of strategic simplicity that is closely tied to the informational demands on agents and provides guidance for the design of scoring rules in practice.

Work in Progress

Information Design in Matching

(with Nicole Immorlica, Brendan Lucier, and Clayton Thomas)