John K.-H. Quah

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Hi.  Thank you for visiting my webpage.  I have moved to Johns Hopkins University.  Please visit my webpage there.





A nonparametric analysis of multi-product oligopolies (with Andrés Carvajal, Rahul Deb, and James Fenske), Economic Theory, Vol. 57(2), 253-277 (2014).  Extension of a paper by the same authors in Econometrica (2013); includes a revealed preference test for multi-product Cournot oligopoly.

Discounting, Values, and Decisions (with Bruno Strulovici), Journal of Political Economy, Vol. 121(5), 896-939 (2013).   Studies how optimal stopping and control vary with the discount rate.

Revealed preference tests of the Cournot model (with Andres Carvajal, Rahul Deb, and James Fenske),  Econometrica, Vol. 81(6), 2351-2379 (2013). There is also a working paper with other results.   Develops a revealed preference test (in the form of a linear program) for the hypothesis that the firms are playing a Cournot game, assuming convex cost functions and observations  generated by changes to industry demand.

Emissions trading with profit-neutral permit allocations (with Cameron Hepburn and Robert Ritz), Journal of Public Economics, Vol. 98, 85--99 (2013).   Examines the impact of an emissions trading scheme (ETS) on equilibrium emissions, output, price, market concentration, and profits in a generalized Cournot model.   Develops formula for the number of emissions permits that have to be freely allocated to firms to neutralize the profit impact of the ETS and relates it to Herfindahl index.

Revealed Preference in a Discrete Consumption Space (with Matthew Polisson), American Economic Journal: Microeconomics, Vol. 5(1), 28-34 (2013).   Shows that an agent maximizing some utility function on a discrete (as opposed to continuous) consumption space will still obey the generalized axiom of revealed preference (GARP).

Aggregating the single crossing property (with Bruno Strulovici), Econometrica, Vol. 80 (5), 2333-2348 (2012).  Introduces a new condition characterizing when the single crossing property is preserved under aggregation.  Applications to optimal decisions under uncertainty, the existence of monotone equilibria in Bayesian-games, etc.. Seminar slides for this paper are available.

Comparative Statics, Informativeness, and the Interval Dominance Order (with Bruno Strulovici),  Econometrica, Vol. 77 (6), 1949-1992 (2009).   Identifies a new way to order functions, called the interval dominance order, that generalizes both the single crossing property and a standard condition used in statistical decision theory.  Provides a unified treatment of the major theorems on monotone comparative statics, the comparison of signal informativeness, and a non-Bayesian theorem on the completeness of increasing decision rules.  Application to optimal stopping time problems where the single crossing property is typically violated. Seminar slides and also slides on background material are available.  Additional related material is found in Comparative Statics with the Interval Dominance Order: Some Extensions (incomplete notes dated 9 December 2007; fuller version to be posted at a later date).

The existence of equilibrium when excess demand obeys the weak axiom, Journal of Mathematical Economics, Vol. 44(3-4), 337-343 (2008).  Elementary proof of equilibrium existence when the excess demand correspondence obeys the weak axiom of revealed preference.

The comparative statics of constrained optimization problems, Econometrica, Vol. 75, No. 2, 401-431 (2007).  Extends the methods of monotone comparative statics to deal with commonly-encountered comparative statics problems involving changes to constraint sets. See also  Additional notes on the comparative statics of constrained optimization problems, Working Paper, Nuffield College, Oxford, No. 2006-W09. 

A contribution to duality theory, applied to the measurement of risk aversion (with Juan Enrique Martinez-Legaz), Economic Theory, Vol. 30, No. 2, 337-362 (2007).   Examines the connection between the curvature properties of an objective function and the ray-curvature properties of its dual.  Characterizes the relationship between an agent’s attitude towards income risks and her attitude towards risks in the underlying consumption space.

Weak Axiomatic Demand Theory, Economic Theory, Vol. 29, No. 3, 677-699 (2006).  Identifies a class of complete but not necessarily transitive preferences which generate demand functions that obey the weak axiom of revealed preference and within which any function obeying the weak axiom can be rationalized.

Homothetic or Cobb-Douglas behavior through aggregation (with Gael Giraud), Contributions to Theoretical Economics, Vol. 3, No. 1, Article 8 (2003).  Shows how consumers' (heterogeneous) preferences in a market could be distributed in such a way that aggregate market demand takes on exact homothetic or Cobb-Douglas properties.

Market demand and comparative statics when goods are normal, Journal of Mathematical Economics, Vol.39, 317-333 (2003).  Explores the consequences of normal demand on comparative statics in exchange, production, and financial economies.

The law of demand and risk aversion, Econometrica, Vol. 71, 713-721 (2003).  Shows that the law of demand can be characterized by a modified version of the Milleron-Mitjuschin-Polterovich condition.  The condition could be interpreted as a measure of differences in risk aversion when an agent encounters different lotteries over commodity bundles in commodity space.

The monotonicity of individual and market demand, Econometrica, Vol. 68, No. 4, 911-930 (July 2000).   Shows that the law of demand  for market demand (market monotonicity) can arise through a range of conditions between two extremes known to guarantee market  monotonicity:  the  Milleron-Mitjuschin-Polterovich conditions on individual preferences and the Hildenbrand conditions on the income distribution.

The law of demand when income is price dependent, Econometrica, Vol. 65, 1421-1442 (November 1997).  Uses a weaker form of the demand heterogeneity assumption employed by Grandmont (1992)  to guarantee the uniqueness and stability of the equilibrium price in exchange and production economies.



Introduction: Symposium on Revealed Preference Analysis (with Alfred Galichon), Economic Theory, Vol. 54(3), 419-423 (2013).   Short survey of revealed preference analysis.

Law of Demand (with Michael Jerison), The New Palgrave Dictionary of Economics, Second Edition (2008).  There is also a working paper of this entry.