I'm an Associate Professor at the University of Colorado Boulder. My research interests focus on the effects of international trade and globalization on workers, consumers, and firms.
Department of Economics
University of Colorado Boulder
256 UCB, Boulder, CO 80309-0256
sergey dot nigai at colorado dot edu
In "From Discrete Choice to Endogenous Distributions: Selection and Heterogeneity", I develop a tractable framework in which heterogeneity within sectors, locations, or occupations emerges endogenously from equilibrium selection, with applications to trade, economic geography, and occupational sorting. The figure on the left illustrates how differences in distributions arise due to selection.
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This paper develops a tractable framework in which heterogeneity, captured by the distribution of agent characteristics within an alternative (sector, location, or occupation), emerges endogenously in equilibrium through selection rather than being imposed exogenously. I show that widely used extreme-value and power-law distributions arise as conditional outcomes of payoff-based discrete choice with multivariate shocks. The framework delivers a one-to-one mapping between equilibrium allocation shares and within-alternative heterogeneity. Because distributions are equilibrium objects, they respond to counterfactual shocks, introducing adjustment margins absent from standard models and generating richer responses, as shown in applications to trade, economic geography, and occupational sorting.
In "Sectoral Transport Mode Elasticities and International Trade" (with Jeong-won Ko and Alec Truax), we estimate sectoral transport mode elasticities for 21 manufacturing sectors using IV methods and relate them to standard trade elasticities. The figure plots our estimates against sectoral trade elasticities.
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We estimate sector‐specific transport-mode elasticities in international trade costs using newly available bilateral trade data disaggregated by mode and sector for 2016–2019. We rely on an instrumental-variable approach that exploits the interaction of global, mode-specific cost shocks with exogenous bilateral geography to identify elasticities for 21 manufacturing sectors. Our estimates reveal substantial heterogeneity, ranging from statistically insignificant values near zero to 11.4, with high value-to-weight sectors exhibiting greater sensitivity to transport-mode cost shocks. We embed these estimates in a multi-country, multi-sector general-equilibrium trade model with endogenous mode choice and input–output linkages. Counterfactual simulations of global changes in air-transport costs show that accounting for sectoral heterogeneity in transport-mode elasticities generates substantial differences in trade outcomes relative to a uniform-elasticity case.
In "Empirical Productivity Distributions and International Trade" (with Peter Egger and Katharina Erhardt) we use micro and macro data to recover country-sector non-parametric productivity distributions and study the role of comparative advantage in shaping trade when technology takes the form of productivity distributions across firms. The figure on the left illustrates recovered CDF's for 15 countries and 17 sectors.
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This paper reassesses the question of the importance of comparative advantage in a model of international trade with heterogeneous firms where productivity is distributed nonparametrically. This assessment rests on a method of isolating empirical productivity distributions for 15 countries and 17 sectors using a combination of firm-level and macroeconomic data together with the structure of the model. In this setting, the effects of technology on trade are substantial and cannot be captured by a small set of technology parameters. On average, comparative advantage accounts for 23% of the observed variation in trade or 70% in the absence of selection effects.