Decoding India’s Low Covid-19 Case Fatality Rate

(with Minu Philip and S. Subramanian), August 2020.

Summary. India’s case fatality rate (CFR) under covid-19 is strikingly low, trending from 3% or more, to a current level of around 2.2%. The world average rate is far higher, at around 4%. Several observers have noted that this difference is at least partly due to India’s younger age distribution. In this paper, we use age-specific fatality rates from comparison countries, coupled with India’s distribution of covid-19 cases to “predict” what India’s CFR would be with those age-specific rates. In most cases, those predictions are lower than India’s actual performance, suggesting that India’s CFR is, if anything, too high rather than too low.

Growth, Automation and the Long-Run Share of Labor

(with Dilip Mookherjee), June 2020. Supplementary Appendix. Slides.

Summary. We present a theory of long run inequality and automation driven by capital accumulation rather than technical progress. At the heart of the theory is a singularity condition that guarantees automation in the production of automated technologies. If that condition is satisfied, the functional share of capital approaches 100% in the long run.

Too Good To Be True? Retention Rules for Noisy Agents

(with Francisco Espinosa), revised September 2020. Supplementary Appendix.

Summary. An agent who privately knows his type (good or bad) seeks to be retained by a principal. A principal seeks to retain good agents. Agents signal their type with some ambient noise, but can alter this noise, perhaps at some cost. Our main finding, that we examine in several extensions, is that in equilibrium,  the principal treats extreme signals in either direction with suspicion, and retains the agent if and only if the signal falls in some intermediate bounded set. In short, she follows the maxim: “if it seems too good to be true, it probably is.”  

Conveying Value Via Categories

(with Paula Onuchic), October 2019.

A sender is about to come into possession of an object of heterogeneous quality. Prior to knowing that quality, she commits to a categorization. That is, she partitions the set of qualities into  subsets — some possibly singletons — and verifiably commits to reveal the element in which the quality belongs. The categories  must be monotone. Our main results fully describe the profit-maximizing categorization  for any pair of priors over object quality held by sender and receiver. We apply these results to the design of educational grades.

A Sovereign Fund for India

(with Parikshit Ghosh), October 2019.

We propose that India build up a sovereign fund, to be invested in portfolios of equity, bonds and other financial assets, and managed professionally as any fund would be managed, subject to certain constraints that we describe in this paper. The proposal to access Indian corporate value consists of two parts: I. A one-time directive that will require every publicly traded Indian company to issue new shares to the government, equal to some fraction (say 10–20%) of their outstanding shares in the mar- ket. II. An ongoing obligation to transfer some given fraction (again 10–20%) of every new share issue — whether in the form of an initial public offering or an expansion of the existing share base — to the India Fund.

Aspirations and Economic Behavior

(with Garance Genicot), December 2019. Forthcoming, Annual Review of Economics.

This paper reviews the literature on aspirations in economics, with a particular focus on socially determined aspirations. The core theory builds on two fundamental principles: (a) aspirations can serve to inspire, but still higher aspirations can lead to frustration and resentment; and (b) aspirations are largely determined by an individual’s social environment. We discuss the implications of this framework for the study of interpersonal inequality, social conflict, fertility choices, risk taking and goal-setting.

Information Aggregation in a Financial Market with General Signal Structure

(with Youcheng Lou, Sahar Parsa, Duan Li and Shouyang Wang), May 2019, forthcoming, Journal of Economic Theory.

Summary. We study a financial market with asymmetric, multidimensional trader signals that have general correlation structure. Each of a continuum of traders belongs to one of finitely many “information groups.” There is a multidimensional aggregate signal for each group. Each trader observes an idiosyncratic signal about the fundamental, built from this group signal. Correlations across group signals are arbitrary. Several existing models serve as special cases, and new applications become possible. We establish existence and regularity of linear equilibrium, and demonstrate that the equilibrium price aggregates information perfectly as noise trade vanishes. Combines and extends results in Parsa and Ray (2017) and Lou, Li and Wang (2017), both mimeo. Online Appendix.

Games of Love and Hate

(with Rajiv Vohra), Journal of Political Economy 128, 1789-1825 (2020).

Dedicated to Tapan Mitra — advisor, colleague and dear friend, whose sense of aesthetics, minimalism and rigor has been an inspiration to us. Tapan Mitra died on February 3, 2019.

Summary. A strategic situation with payoff-based externalities is one in which a player’s payoff is a function of her own action and the payoffs of other players. Every action profile therefore induces an interdependent utility system. A strategic situation is continuous if each such utility system is continuous. If each utility system is bounded, with a unique payoff solution for every action profile, we call the strategic situation coherent, and if the same condition also applies to every subset of players, we call the situation sub-coherent. A coherent, sub-coherent and continuous situation generates a standard normal form, referred to as a game of love and hate. Our central theorem states that every equilibrium of a game of love and hate is Pareto optimal, in sharp contrast to the general prevalence of inefficient equilibria in the presence of externalities. While externalities are restricted to flow only through payoffs there are no other constraints: they could be positive or negative, or of varying sign. We further show that our coherence, sub-coherence and continuity requirements are tight.

Maximality in the Farsighted Stable Set

(with Rajiv Vohra)   Econometrica 87(5), 1763–1779 Online Appendix.

SummaryThe stable set of von Neumann and Morgenstern can be extended to cover farsighted coalitional deviations, as proposed by Harsanyi (1974), and more recently reformulated by Ray and Vohra (2015). However,  while coalitional deviations improve on existing outcomes, coalitions might do even better by moving elsewhere. Or other coalitions might intervene to impose their favored moves. We show that every farsighted stable set satisfying some reasonable, and easily verifiable, properties is unaffected by the imposition of this stringent maximality requirement.