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.
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
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
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