Two cornerstones of empirical and policy analysis of firms in industrial organization, macro and labor are the determinants of the firm size distribution, and the determinants of sorting between workers and firms. We propose a unifying theory of production where management resolves a tradeoff between hiring more versus better workers. The span of control or size is therefore intimately intertwined with the sorting pattern. We provide a condition for sorting that captures this tradeoff between the quantity and quality of workers and that generalizes Becker’s sorting condition. A system of differential equations determines the equilibrium allocation, the firm size and wages, and allows us to characterize the allocation of the quality and quantity of labor to firms of different productivity. We show that our model nests a large number of widely used existing models. We also augment the model to incorporate labor market frictions in the presence of sorting with large firms.
Assortative Matching with Large Firms
Econometrica. 2018 86(1): 85-132. With Jan Eeckhout.
When heterogeneous firms can choose both how many and which workers to hire, we illustrate consequences for firm-size and wage inequality.
Note a correction for the condition with capital: corrigendum.
American Economic Review, 2015, Vol 105 (10), 3030-3060. With Leo Kaas. We propose a tractable competitive search model with heterogeneous multi-worker firms, and investigate firm growth and business cycles. Go to paper
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
International Economic Review, 2012, Vol 53 (1), 1-21. With M. Galenianos. We study a finite directed-search wage posting game among heterogeneous firms (allowing for risk aversion, moral hazard,…), including limit theorems. Go to paper
Journal of Economic Theory, 2009, 114(2), pp. 445-471. With Manolis Galenianos. We study wage dispersion and (in)efficiency in directed search when workers can strategically apply for multiple jobs but firms can only make one offer. Go to paper
Review of Economic Studies, 2015, Vol 82 (2), 659-692. With Fane Groes and Iourii Manovskii. Occupational mobility is highest for high and low earners, and the former move “up” and the latter “down” as in models of vertical re-sorting. Go to paper
Review of Economic Studies, 2011, Vol. 78 (3), 872-906. With Jan Eeckhout. Wage and employment data can identify the strength of sorting in search models, though two-sided fixed effects are always mis-specified. 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
International Economic Review, 2011, 52(1), pp 85-104. With M. Galenianos and G. Virag. [technical appendix] In directed search with a finite population, minimum wages improve employment but reduce output and efficiency, and reverse for unemployment benefits. Go to paper