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Economic Theory

Economic theory is at the center of the Cowles Foundation’s research mission. The Economic Theory group at Yale has a distinguished legacy of outstanding scholars and is characterized by a large faculty whose research spans virtually all specializations.

Yale has one of the largest and finest research groups in economic theory in the world. Our faculty have research interests in all the major fields of microeconomic theory, including but not limited to decision theory, general equilibrium, game theory, contract theory, mechanism design, information design, learning, matching, and misspecified models. The Economics Department has a long tradition in training aspiring theorists and has produced top scholars in the field.

Following its longstanding tradition of supporting research in theoretical economics, the Cowles Foundation provides a uniquely supportive environment for work in microeconomic theory. The Cowles Foundation funds a regular influx of short term and long term academic visitors, postdocs, and doctoral students from other institutions, who contribute to the economic theory research community.

Seminars and Conferences

The Department runs two weekly workshop meetings in economic theory. The Microeconomic Theory Workshop hosts speakers from Yale and other universities to report on their latest research and to provide overviews of developing research areas. The Micro Theory Lunch enables graduate students, faculty, and outside visitors to present their work at various stages of development. In addition, the program runs a weekly Micro Theory Breakfast, intended primarily for our graduate students to assist them in moving forward with their own research agendas.

Every year, the Economic Theory Program hosts a summer conference to bring together top economists in the field to present new research. Recent conferences have covered a wide variety of topics, such as novel approaches to mechanism/information design, foundations of belief elicitation, information provision in markets and political settings, manipulability of voting schemes, firm coalitions and market structures, robust tools for welfare analysis, organizational culture, and more.

For more information about the Economic Theory summer conferences, see the Cowles Conferences and Workshops page.

Graduate Teaching and Research

The Department offers an intensive two-course sequence for all students in the PhD program: Microeconomic Theory I (Econ 500a) and II (Econ 501b) is a two-course core sequence. Material covered includes consumer and producer theory, choice under uncertainty, general equilibrium theory, game theory, information economics, and mechanism design. The Department also offers two other two-part course sequences for advanced theory students. Advanced Microeconomics I (Econ 520a) and II (Econ 521b) examine in more depth foundational issues in game theory, information economics, mechanism design, and social choice. Mathematical Economics I (Econ 530a) and II (Econ 531b) focus on issues in general equilibrium theory. Typically, these sequences are taken by PhD students in the second year, including both those who will end up specializing in microeconomic theory and those who will do applied research using advanced tools of microeconomic analysis.

For detailed field descriptions, please see the Department’s PhD Program Page.

Latest Publications

Discussion Paper
Abstract

With uncertainty about persistence, we show that forecasts necessarily become more persistent and over-react at long horizons. For these reasons, correctly specified and Bayesian forecasts may under-react at short horizons and over-react at long horizons. These results provide a unified explanation for several asset pricing and forecasting puzzles, including: (i) the excess responsiveness of long-horizon rates to short rates, (ii) the dominance of apparent term premia for long-term rates, (iii) the ex post predictability of bond yields, (iv) the excess volatility of long-horizon forward prices, (v) the excess persistence of long-horizon forecasts, and (vi) the over-reaction of long-horizon forecasts.

Discussion Paper
Abstract

A monopolist offers personalized prices to consumers with unit demand. Consumers differ in their values, costs, and \emph{protected characteristics}---such as race or gender. The seller is subject to a non-discrimination constraint: consumers with the same cost, but different protected characteristics must face identical price distributions. Such regulations are present in markets like credit or insurance. We characterize the optimal pricing rule. Under this rule, surplus accrues to both protected groups, but only to those with intermediate values. Strengthening the constraint to cover transaction prices redistributes surplus, harming the low-value group and benefiting the high-value group. Meanwhile, prohibiting the use of protected characteristics as pricing inputs instead of regulating outputs harms the low-value group.

Discussion Paper
Abstract

We build a general equilibrium model in which firms endogenously choose whether to target prices or quantities. We characterize how these choices of organizational targets depend on firms' uncertainty about microeconomic and macroeconomic factors. In equilibrium, the transmission of both nominal and real shocks hinges on firms' organizational targets. For example, under otherwise identical microfoundations, money is neutral under quantity targets and non-neutral under price targets. We further characterize how targets shape firms' strategic interactions and prove that the macroeconomic uncertainty that arises from each choice of targets reinforces incentives to choose that target. That is, choices of organizational targets are strategic complements. For this reason, monetary policy aimed at stabilization can backfire by inducing a regime shift that renders it ineffective. A simple quantification suggests that incentives over organizational targets can vary markedly at business-cycle frequencies and help explain the state-dependent pass-through of monetary shocks to prices and output.

Discussion Paper
Abstract

We study optimization problems in which a linear functional is maximized over probability measures that are dominated by a given measure according to an integral stochastic order in an arbitrary dimension. We show that the following four properties are equivalent for any such order: (i) the test function cone is closed under pointwise minimum, (ii) the value function is affine, (iii) the solution correspondence has a convex graph with decomposable extreme points, and (iv) every ordered pair of measures admits an order-preserving coupling. As corollaries, we derive the extreme and exposed point properties involving integral stochastic orders such as multidimensional mean-preserving spreads and stochastic dominance. Applying these results, we generalize Blackwell's theorem by completely characterizing the comparisons of experiments that admit two equivalent descriptions—through instrumental values and through information technologies. We also show that these results immediately yield new insights into information design, mechanism design, and decision theory.

Discussion Paper
Abstract

As AI systems enter institutional workflows, workers must decide whether to delegate task execution to AI and how much effort to invest in verifying AI outputs, while institutions evaluate workers using outcome-based standards that may misalign with workers’ private costs. We model delegation and verification as the solution to a rational worker’s optimization problem, and define worker quality by evaluating an institution-centered utility (distinct from the worker’s objective) at the resulting optimal action. We formally characterize optimal worker workflows and show that AI induces phase transitions, where arbitrarily small differences in verification ability lead to sharply different behaviors. As a result, AI can amplify workers with strong verification reliability while degrading institutional worker quality for others who rationally over-delegate and reduce oversight, even when baseline task success improves and no behavioral biases are present. These results identify a structural mechanism by which AI reshapes institutional worker quality and amplifies quality disparities between workers with different verification reliability.

Discussion Paper
Abstract

As AI systems shift from tools to collaborators, a central question is how the skills of humans relying on them change over time. We study this question mathematically by modeling the joint evolution of human skill and AI delegation as a coupled dynamical system. In our model, delegation adapts to relative performance, while skill improves through use and decays under non-use; crucially, both updates arise from optimizing a single performance metric measuring expected task error. Despite this local alignment, adaptive AI use fundamentally alters the global stability structure of human skill acquisition. Beyond the high-skill equilibrium of human-only learning, the system admits a stable low-skill equilibrium corresponding to persistent reliance, separated by a sharp basin boundary that makes early decisions effectively irreversible under the induced dynamics. We further show that AI assistance can strictly improve short-run performance while inducing persistent long-run performance loss relative to the no-AI baseline, driven by a negative feedback between delegation and practice. We characterize how AI quality deforms the basin boundary and show that these effects are robust to noise and asymmetric trust updates. Our results identify stability, not incentives or misalignment, as the central mechanism by which AI assistance can undermine long-run human performance and skill.