Sorting versus screening: Search frictions and competing mechanisms

In a market where sellers compete by posting trading mechanisms, we allow for a general search technology and show that its features crucially affect the equilibrium mechanism. Price posting prevails when meetings are rival, i.e., when a meeting by one buyer reduces another buyer’s meeting probability. Under price posting buyers reveal their type by sorting ex ante. Only if the meeting technology is sufficiently non-rival, price posting is not an equilibrium. Multiple buyer types then visit the same sellers who screen ex post through auctions

Identifying Sorting - In Theory

We argue that using wage data alone, it is virtually impossible to identify whether Assortative Matching between worker and firm types is positive or negative. In standard competitive matching models the wages are determined by the marginal contribution of a worker, and the marginal contribution might be higher or lower for low productivity firms depending on the production function. For every production function that induces positive sorting we can find a production function that induces negative sorting but generates identical wages. This arises even when we allow for non-competitive mismatch, for example due to search frictions. 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. While we show analytically that standard fixed effects regressions are not suitable to recover the strength of sorting, we propose an alternative procedure that measures the strength of sorting in the presence of search frictions independent of the sign of the sorting.sorting, assortative matching, identification, linked employer-employee data, interpretation of fixed-effects

Identifying Sorting: In Theory

We argue that using wage data alone, it is virtually impossible to identify whether Assortative Matching between worker and firm types is positive or negative. In standard competitive matching models the wages are determined by the marginal contribution of a worker, and the marginal contribution might be higher or lower for low productivity firms depending on the production function. For every production function that induces positive sorting we can find a production function that induces negative sorting but generates identical wages. This arises even when we allow for non-competitive mismatch, for example due to search frictions. 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. While we show analytically that standard fixed effects regressions are not suitable to recover the strength of sorting, we propose an alternative procedure that measures the strength of sorting in the presence of search frictions independent of the sign of the sorting.sorting, assortative matching, identification, linked employer-employee data, interpretation of fixed-effects

Sorting and Decentralized Price Competition

We investigate under which conditions price competition in a market with matching frictions leads to sorting of buyers and sellers. Positive assortative matching obtains only if there is a high enough degree of complementarity between buyer and seller types. The relevant condition is root-supermodularity; i.e., the square root of the match value function is supermodular. It is a necessary and sufficient condition for positive assortative matching under any distribution of buyer and seller types, and does not depend on the details of the underlying matching function that describes the search process. The condition is weaker than log-supermodularity, a condition required for positive assortative matching in markets with random search. This highlights the role competition plays in matching heterogeneous agents. Negative assortative matching obtains whenever the match value function is weakly submodular.Competitive Search Equilibrium. Directed Search. Two-Sided Matching. Decentralized Price Competition. Root-Supermodularity.

Occupational Choice and Development

The rise in world trade since 1970 has raised international mobility of labor services. We study the effect of such a globalization of the world's labor markets. We find that when people can choose between wage work and managerial work, the output gains are U-shaped: A worldwide labor market raises output by more in the rich and the poor countries, and by less in the middle-income countries. This is because the middle-income countries experience the smallest change in the factor-price ratio, and where the option to choose between wage work and managerial work has the least value in the integrated economy. Our theory also establishes that after economic integration, the high skill countries see a disproportionate increase in managerial occupations. Using aggregate data on GDP, openness and occupations from 115 countries, we find evidence for these patterns of occupational choice.

Dominant firms in the digital age

Since 1980, the world economy has experienced an increase of dominant firms. Dominant firms face limited competition in their market and exert monopoly power. Why has this happened, and why did it start in 1980? The rise of dominant firms has a direct impact on customers who pay higher prices, but it also has far-reaching implications for the macroeconomy. Widespread market power leads to wage stagnation and a decline in the labor share, it increases wage inequality, it slows down business dynamism, it reduces the number of startup firms and lowers innovation. In this public paper Eeckhout reviews the determinants of the rise of dominant firms, discusses the causes and consequences, and proposes directions for policy solutions

Bargaining Over Public Goods

In a simple public good economy, we propose a natural bargaining procedure whose equilibria converge to Lindahl allocations as the cost of bargaining vanishes. The procedure splits the decision over the allocation in a decision about personalized prices and a decision about output levels for the public good. Since this procedure does not assume price-taking behavior, it provides a strategic foundation for the personalized taxes inherent to the Lindahl solution to the public goods problem.

Spatial Sorting: Why New York, Los Angeles and DetroitAttract the Greatest Minds as well as the Unskilled

We propose a theory of skill mobility across cities. It predicts the well documented city size-wage premium: the wage distribution in large cities first-order stochastically dominates that in small cities. Yet, because this premium is reflected in higher house prices, this does not necessarily imply that this stochastic dominance relation also exists in the distribution of skills. Instead, we find there is second-order stochastic dominance in the skill distribution. The demand for skills is non-monotonic as our model predicts a “Sinatra” as well as an “Eminem” effect: both the very high and the very low skilled disproportionately sort into the biggest cities, while those with medium skill levels sort into small cities. The pattern of spatial sorting is explained by a technology with a varying elasticity of substitution that is decreasing in skill density. Using CPS data on wages and Census data on house prices, we find that this technology is consistent with the observed patterns of skills.matching theory, sorting, general equilibrium, population dynamics, cities, wage distribution

Bargaining over Public Goods

In a simple public good economy, we propose a natural bar- gaining procedure, the equilibria of which converge to Lin- dahl allocations as the cost of bargaining vanishes. The pro- cedure splits the decision over the allocation in a decision about personalized prices and a decision about output levels for the public good. Since this procedure does not assume price-taking behavior, it provides a strategic foundation for the personalized taxes inherent in the Lindahl solution to the public goods problem.public goods; alternating offers bargaining

Inequality

In a growth model, rent-grabbing and free riding can give rise to inequality in productivity and firm size. Inequality among firms affects a firm's incentive to free ride or to grab rents, and, hence, the incentive to invest in research and training We follow Lucas and Prescott (1971) and Hayashi (1982) and assume constant returns in production and in adjustment costs for investment, and perfect capital markets. Our conclusion, however, differs starkly from theirs: Average Tobin's q generally exceeds marginal q. That is, the unit value of capital is lower in big firms, and evidence dating back to Fazzari, Hubbard, and Petersen (1988) supports this claim quite decisively. Such evidence is usually taken to imply that small firms invest at a rate lower than its perfect capital market rate. In our model, however, it arises because small firms rely more on copying than big firms do: The marginal product of capital is equal across firms, but its average product is higher than that because small firms get a disproportionately high external benefit.