Bio

I am a professor of political science and economics at the University of Rochester, and I am a research associate of the W. Allen Wallis Institute of Political Economy. I was director of the W. Allen Wallis Institute of Political Economy for the period 2002--2012, and I was co-managing editor for the journal Social Choice and Welfare for the period 2008--2015. I received my PhD in social science from the California Institute of Technology in 1995. My specializations are game theory, political economy, and social choice theory. My current work is on equilibrium existence in non-cooperative games, dynamic models of bargaining and elections, multi-dimensional spatial models of political competition, and informational aspects of voting and elections.




Recent updates

In this section, I provide links to papers and other content added in the last year or so.

June 15, 2017 Subgame-Perfect Equilibrium in Games with Almost Perfect Information: Dispensing with Public Randomization” (with Paulo Barelli)   Harris, Reny, and Robson (1995) show that correlated subgame perfect equilibrium exist in a general class of dynamic games. We show that when nature’s moves are atomless, every such equilibrium can be de-correlated: there is a payoff-equivalent subgame-perfect equilibrium of the original game. As a corollary, we obtain an existence result of He and Sun (2016) for subgame perfect equilibria in games with atomless moves by nature.

May 31, 2017 Lobbying and Policy Extremism in Repeated Elections” (with Peter Bils and Gleason Judd)   We investigate the effect of lobbying on policy choices in an infinite-horizon model of elections. We find that when the effectiveness of money is fixed, if office incentives become large, then policy choices converge to the median. However, if office incentives are fixed and the effectiveness of money becomes large, then polarized equilibria that exhibit arbitrarily extreme policy choices by all politician types can be supported. Here are some slides from a talk.

May 31, 2017The Political Economy of Dynamic Elections: Accountability, Commitment, and Responsiveness” (with Cesar Martinelli)   This article is forthcoming at the Journal of Economic Literature. It contains a survey and synthesis of the literature on electoral accountability, i.e., repeated elections in which politicians cannot commit their policy choices. We focus on conditions under which policy choices of office holders nevertheless reflect the preferences of the median voter.

May 31, 2017The Political Economy of Dynamic Elections: A Survey and Some New Results” (with Cesar Martinelli)   This is a longer version of the above JEL paper with expanded discussion and technical detail, including many proofs omitted from the shorter paper.

May 31, 2017 Electoral Accountability and Responsive Democracy” (with Cesar Martinelli)   We analyze a canonical two-period model of elections in which politicians’ preferences and actions are imperfectly observed by voters, i.e., elections are subject to adverse selection and moral hazard. We establish existence of electoral equilibrium, and we give a characterization of equilibria. We show that as politicians become more office motivated, policy is responsive to voter preferences in the sense that the expected level of effort exerted by politicians in the first period becomes arbitrarily large.

May 31, 2017Existence and Indeterminacy of Markovian Equilibria in Dynamic Bargaining Games” (with Vincent Anesi)   We show that if certain gradient restrictions hold at an alternative, then when players are sufficiently patient, there is a continuum of equilibria with absorbing sets arbitrarily close to that alternative. Revisions include a weakening of the original gradient restrictions, and results that deliver a continuum of Pareto efficient equilibria. Here are some slides from a talk.

May 31, 2017 Directional Equilibria   We propose a new solution concept (directional equilibrium) for the multidimensional spatial model. We establish connections the core, Pareto optimality, existence, and generic local uniqueness and stability, and we provide non-cooperative foundations. Updates include expanded literature references and reduction of some technical material on generic properties of directional equilibria. Here is a working paper with results on generic properties, here are some slides from a longer talk, and here are slides from a shorter talk.

November 10, 2016 A Simple Example of a Finite Stochastic Game with Sequential Moves and No Pure-strategy Stationary Markov Perfect Equilibrium,”   A small example that might be interesting to someone.

October 28, 2016 Multidimensional Tug of War” (with Jacque Gao)   We analyze a game in which players exert effort to pull a collective outcome in a multidimensional space in their preferred direction. We prove existence and uniqueness of equilibrium and characterize the outcome as risk aversion varies. The latest version includes additional references to the literature.

October 25, 2016 Term Limits and Bounds on Policy Responsiveness in Dynamic Elections   I examine the possibility of policy responsiveness in an infinite-horizon model of elections with a two-period term limit, under the assumption of adverse selection and moral hazard. I characterize equilibria and prove existence of equilibrium, pointing out and correcting an error in the proof of Banks and Sundaram (1998). The current version contains corrections of many errors in the previous version. Here are some slides from a talk.

September 6, 2016 A Note on the Pareto Manifold in the Spatial Model of Politics”   I provide sufficient conditions for the Pareto set to exhibit a manifold structure near a Pareto optimal alternative -- the analysis takes utility functions as given, rather than making genericity claims. I then investigate a natural parameterization of the Pareto manifold and the corresponding parameterized utilities. In contrast to Smale (1976), I do not assume an economic environment; rather, I consider a general model that includes the spatial model of politics as a special case.

February 24, 2016 Notes on Spatial Bargaining and Stochastic Games”   These notes present the theory of bargaining in the spatial model of politics, with a special focus on issues of equilibrium existence, including a fairly comprehensive introduction to the theory of stochastic games. Changes from the previous version are limited to a number of typo corrections.

February 23, 2016 Existence of Stationary Bargaining Equilibria”   An existence theorem for stationary equilibria in a general class of bargaining models assuming only continuity and compactness conditions -- no convexity or comprehensiveness assumptions are used. The current version has been shortened and has benefited from the correction of several minor errors. Here are some slides from a shorter talk that was pretty good. Here are some slides from a longer talk that was probably less clear.

February 23, 2016 Limits of Acyclic Voting   An Arrovian result for acyclic social choice under the independence of irrelevant alternatives. This is an abbreviated version of “Limits of Acyclic Voting and Nash Implementation,” less the implementation result, plus results for saturated domains and large numbers of alternatives. A recent addition is a generalization of the acyclicity axiom that precludes cycles of an arbitrary, fixed length.

February 14, 2016 Dynamic Bargaining and Stability with Veto Players (with Vincent Anesi)   We establish ergodic properties of equilibria in the finite environment of Anesi (2012), and we show that when players are patient and the voting rule is oligarchical, a set is a von Neumann-Morgenstern solution if and only if it consists of the absorbing points of an equilibrium. We also establish this result in the model with general voting rule and a persistent agenda setter.

October 11, 2015 Sequential Median Location   This short note shows that in sequential location games in one dimension with single-peaked preferences, if the order of location alternates between agents on one side of the median and the other, then the unique pure strategy subgame perfect equilibrium outcome is the median. The result extends to sequential play of any Condorcet consistent game and to mixed strategies.

May 28, 2015 Purification of Bayes Nash Equilibrium with Correlated Types and Interdependent Payoffs (with Paulo Barelli)   In Bayesian games with a product structure, we provide conditions under which Bayes-Nash equilibria can be purified. Moreover, we show that equilibria in undominated strategies exist, and we provide a purification result for such equilibria. Here are some slides from a talk.

May 26, 2015 Preference Exclusions for Social Rationality”   I provide conditions for transitive and acyclic voting under general preference restrictions, and I extend known results for value restriction, single peakedness, weak single peakedness, and order restriction. For median voter theorems and representative voter theorems, see “Value Restriction, Median Voters, and the Core.”

March 18, 2015 May’s Theorem in One Dimension   I provide characterizations of majority rule using the axioms of Kenneth May, but assuming single-peaked preferences and substituting transitivity properties for the more controversial positive responsiveness axiom. The current version drops the incorrect Proposition 3 from the previous version, and it adds Propositions 3 and 4 and Corollary 11, which give characterizations of majority rule using non-negative responsiveness.

December 18, 2014 Notes on Social Choice Rules”   Notes on social choice rule for PSC 408. Various examples and axioms are considered, with a special focus on non-manipulability. Changes to the previous version consist mainly of numerous typo corrections.

December 18, 2014 “Formal Models in Political Science”   Lecture notes for my undergraduate course on formal political theory, PSC 281/ECO 282. These are substantially revised from the previous version, deleting material on the Nash social welfare function and adding a small amount of material on general equilibrium theory and game theory.

November 26, 2014 A Folk Theorem for the One-dimensional Spatial Bargaining Model” (with Seok ju Cho)   We establish a folk theorem when voting is simultaneous and publicly observed; of note, in the bad status quo model, discount factors need only be positive to support every interior alternative as an equilibrium outcome of the model. Minor updates include rewriting of the appendix to improve readability.

November 25, 2014Extremal Choice Equilibrium with Applications to Large Games, Stochastic Games, and Endogenous Institutions” (with Paulo Barelli)   The new version includes expanded discussion of applications to large games, stochastic games, and endogenous institutions. And of course, corrections of a number of typos.

November 10, 2014 Dynamic Elections and the Limits of Accountability” (with Jean Guillaume Forand)   We establish equilibrium existence in a model of dynamic elections with an endogenously evolving state variable, and we give conditions under which electoral equilibria solve a representative dynamic programming problem. We give several examples of novel types of political failure.

November 10, 2014 A Survey of Equilibrium Analysis in Spatial Models of Elections   I provide an overview of results on Downsian and probabilistic voting models for different candidate objective functions, with a special focus on existence of equilibrium. The new version fixes several typos.

October 15, 2014Basic Concepts in Mathematical Analysis: A Tourist Brochure”   A brief tour of mathematics that starts from the basics and could be helpful for Ph.D. students in economics or political science. The current version contains corrections to a number of typos.

October 15, 2014 Abbreviated Notes on Social Choice”   These notes distill some of the fundamental results in social choice theory. They include novel results on preference exclusions, acyclicity, and weak single-peakedness. Revisions include corrections to a new proof of Arrow’s theorem, adjustments to Exclusion condition T, and corrections of several typos.

September 13, 2014 Markovian Elections” (with Jean Guillaume Forand)   We establish equilibrium existence and median voter results in a model of dynamic elections with an endogenously evolving state variable. The framework is quite general, and we give several examples of different types of political failure. Revisions to the previous version include a restatement of Corollary 1 (which was previously incorrect). Coming soon: this paper is being split in two, with expanded results and examples.