Assortative Matching between workers and firms provides evidence of the complementarities or substitutes in production. The presence of complementarities is important for policies that aim to achieve the optimal allocation of resources, for example unemployment insurance. We argue that using wage data alone, it is virtually impossible to identify whether Assortative Matching is positive or negative. Even though we cannot identify the sign of the sorting, we can identify the strength, i.e., the magnitude of the cross-partial, and the associated welfare loss. We show first that the wage for a given worker is non-monotonic in the type of his employer. This is due to the fact that in a sorting model, wages reflect the opportunity cost of mismatch. We show analytically that this non-monotonicity prevents standard firm fixed effects to correlate with the true type of the firm. We then propose an alternative procedure that measures the strength of sorting in the presence of search frictions. Knowing the strength of sorting facilitates the measurement of the output loss due to mismatch.
Journal of Political Economy, 2017, 124(1), 224-264. With G. Grossman & E. Helpman. (simulations, matlab). We introduce two-sided heterogeneity into a Hecksher-Ohlin-style trade model to study factor reallocation and wage inequality within and across sectors. Go to paper
Quarterly Journal of Economics, 2008/123(2), pp. 621-661. With A. Postlewaite. [technical appendix] In a model of social learning, the better informed (wealthier) consumers get preferential service because their consumption signals high quality to others. Go to paper
Econometrica, 2019 87(4): 1081-1113. With J. Greenwood, C. Santos and M. Tertilt A calibrated equilibrium search model of an HIV/AIDS epidemic is developed to analyze the direct impact and the behavioral adjustment to policies. Go to paper
American Economic Review P&P, 2017, 107(5): 158–162 With J. Greenwood, C. Santos & M. Tertilt. In a quantitative equilibrium model of sexual behavior and HIV/AIDS transmission we study policies that encourage long-term partnerships. Go to paper
Journal of Monetary Economics, 2008, Vol. 55, pp. 1054-1066. With M. Galenianos. We characterize price dispersion and welfare in a monetary model with private information: inflation is regressive even though the rich hold more money. Go to paper
Journal of Economic Theory, 2010/145, 1354-1385. With Jan Eeckhout. Search affects competing mechanisms: if meetings with low types reduce those of high types, price posting and market separation replace auctions. Go to paper
Econometrica, 2015, Vol 83 (5), 1849-1875. With K. Kim. [online appendix] We introduce cheap-talk into a market game and study if the equilibrium can replicate the constraint efficient allocation under (reserve) price posting. Go to paper