Search

Several externalities arise when agents shield optimally to avoid infection during an epidemic. We classify externalities into static and dynamic and compare the decentralized and optimal solutions when agents derive utility from social interaction. For low infection costs agents shield too little; for high costs they shield too much because of a “rat race to shield”: they delay social action until other agents contract the disease and society reaches herd immunity. Other externalities drive more wedges between the private and social outcomes. The expectation of a fully effective vaccine that ends the disease faster changes results, reversing excessive shielding.

This paper studies the matching of workers within the firm when the productivity of workers depends on how well they match with their co-workers. The firm acts as a coordinating device and derives value from this role. It is shown that a worker's contribution to firm value changes over time in a non-trivial way as co-workers are replaced by new workers. The paper derives optimal hiring and replacement policies, including an optimal stopping rule, and characterizes the resulting equilibrium in terms of worker flows, firm output and the distribution of firm values. Simulations of the model reveal a rich pattern of worker turnover dynamics and their connections to the resulting firm values distribution. The paper stresses the role of horizontal differences in worker productivity, which are different from vertical, assortative matching issues. It derives the rent from organizational capital, with worker complementarities playing a key role. We compare the model to match-specific productivity models and explore the essential differences, with the emphasis laid on worker interactions and complementarities.

The Great Recession has indicated that firms' leverage and access to finance are important for hiring and firing decisions. It is now empirically established that bank lending is correlated to employment losses when credit conditions deteriorate. We provide further evidence of this drawing on a new dataset that we assembled on employment adjustment and financial positions of European firms. Yet, in the Diamond Mortensen Pissarides (DMP) model there is no role for finance. All projects that display positive net present values are realized and financial markets are assumed to be perfect. What if financial markets are not perfect? Does a different access to finance influence the firm's hiring and firing decisions? The paper uses the concept of limited pledgeability proposed by Holmstrom and Tirole to integrate financial imperfections and labor market imperfections. A negative shock wipes out the firm's physical capital and leads to job destruction unless internal liquidity was accumulated by firms. If firms hold liquid assets they may thus protect their search capital, defined as the cost of attracting and hiring workers. The paper explores the trade-off between size and precautionary liquidity holdings in both partial and general equilibrium. We find that if labor market frictions disappear, so does the motive for firms to hold liquidity. This suggests a fundamental complementarity between labor market frictions and holding of liquid assets by firms.

This paper analyses the interaction between internal agency problems within firms and external search frictions when workers have private information. We show that the allocation of resources is determined by a modified Hosios Rule. We then analyze the effect of changes in the macro economic variables on the wage contract and the unemployment rate. We find that private information may increase the responsiveness of the unemployment rate to changes in productivity. The incentive power of the wage contracts is positively related to high productivity, low unemployment benefits and high search frictions.