The labor market occupies center stage in modern theories of fluctuations. The most important phenomenon to explain and understand in a recession is the sharp decline in employment and jump in unemployment. This chapter for the Handbook of Macroeconomics considers explanations based on frictions in the labor market. Earlier research within the real business cycle paradigm considered frictionless labor markets where fluctuations in the volume of work effort represented substitution by households between work in the market and activities at home. A preliminary section of the chapter discusses why frictionless models are incomplete they fail to account for either the magnitude or persistence of fluctuations in employment. And the frictionless models fail completely to describe unemployment. The evidence suggests strongly that consideration of unemployment as a third use of time is critical for a realistic model. The two elements of a theory of unemployment are a mechanism for workers to lose or leave their jobs and an explanation for the time required for them to find new jobs. Theories of mechanism design or of continuous re-bargaining of employment terms provide the first. The theory of job search together with efficiency wages and related issues provides the second. Modern macro models incorporating these features come much closer than their predecessors to realistic and rigorous explanations of the magnitude and persistence of fluctuations.

Labor Markets and Business Cycles integrates search and matching theory with the neoclassical growth model to better understand labor market outcomes. Robert Shimer shows analytically and quantitatively that rigid wages are important for explaining the volatile behavior of the unemployment rate in business cycles. The book focuses on the labor wedge that arises when the marginal rate of substitution between consumption and leisure does not equal the marginal product of labor. According to competitive models of the labor market, the labor wedge should be constant and equal to the labor income tax rate. But in U.S. data, the wedge is strongly countercyclical, making it seem as if recessions are periods when workers are dissuaded from working and firms are dissuaded from hiring because of an increase in the labor income tax rate. When job searches are time consuming and wages are flexible, search frictions--the cost of a job search--act like labor adjustment costs, further exacerbating inconsistencies between the competitive model and data. The book shows that wage rigidities can reconcile the search model with the data, providing a quantitatively more accurate depiction of labor markets, consumption, and investment dynamics. Developing detailed search and matching models, Labor Markets and Business Cycles will be the main reference for those interested in the intersection of labor market dynamics and business cycle research.

This report quantifies labor mobility costs in developing countries and simulates the implied adjustment paths of employment and wages following a change in trade policy. High mobility costs are shown to reduce the potential gains to trade reform.

We build a three-state general equilibrium model of the aggregate labor market that features both standard labor supply forces and labor market frictions. Our model matches key features of the cyclical properties of employment, unemployment, and nonparticipation as well as those of gross worker flows across these three labor market states. Our key finding is that shocks to labor market frictions play a dominant role in accounting for labor market fluctuations. This is in contrast to the focus of the traditional RBC literature, which emphasized how employment fluctuations arise as a consequence of labor supply responses to price changes induced by TFP shocks.

Emerging economies are characterized by higher consumption and real wage variability relative to output and a strongly countercyclical current account. A real business cycle model of a small open economy that embeds a Mortensen-Pissarides type of search-matching frictions and countercyclical interest rate shocks can jointly account for these regularities. In the face of countercyclical interest rate shocks, search-matching frictions increase future employment uncertainty, improving workers’ incentive to save and generating a greater response of consumption and the current account. Higher consumption response in turn feeds into larger fluctuations in the workers’ bargaining power while the interest rates shocks lead to variations in the firms’ willingness to hire; both of which contribute to a highly variable real wage.

An integrated framework to study the theoretical and quantitative properties of economies with frictions in labor, financial, and goods markets. This book offers an integrated framework to study the theoretical and quantitative properties of economies with frictions in multiple markets. Building on analyses of markets with frictions by 2010 Nobel laureates Peter A. Diamond, Dale T. Mortensen, and Christopher A. Pissarides, which provided a new theoretical approach to search markets, the book applies this new paradigm to labor, finance, and goods markets. It shows, in particular, how frictions in different markets interact with each other. The book first covers the main developments in the analysis of the labor market in the presence of frictions, offering a systematic analysis of the dynamics of this environment and explaining the notion of macroeconomic volatility. Then, building on the generality and simplicity of the search analysis, the book adapts it to other markets, developing the tools and concepts to analyze friction in these markets. The book goes beyond the traditional general equilibrium analysis of markets, which is often frictionless. It begins with the standard analysis of a single market, and then sequentially integrates more markets into the analysis, progressing from labor to financial to goods markets. Along the way, the book provides a number of useful results and insights, including the existence of a direct link between search frictions and the degree of volatility in the economy.

During the Great Recession, the interactions between housing, labor and entry highlight the existence of narrow propagation channels between these markets. The aim of this thesis is to shed a light on labor market interactions with firm entry and financial business cycles, by building on the recent theoretical and empirical of DSGE models. In the first chapter, we have found evidence of the key role of the net entry as an amplifying mechanism for employment dynamics. Introducing search and matching frictions, we have studied from a new perspective the cyclicality of the mark-up compared to previous researches that use Walrasian labor market. We found a less countercyclical markup due to the acyclical aspect of the marginal cost in the DMP framework and a reduced role according to firm's entry in the cyclicality of the markup. In the second chapter, we have linked the borrowing capacity of households to their employment situation on the labor market. With this new microfoundation of the collateral constraint, new matches on the labor market translate into more mortgages, while separation induces an exclusion from financial markets for jobseekers. As a result, the LTV becomes endogenous by responding procyclically to employment fluctuations. We have shown that this device is empirically relevant and solves the anomalies of the standard collateral constraint. In the last chapter, we extend the analysis developed in the previous one by integrating collateral constrained firms in order to have a more complete financial business cycle. The first result is that an entrepreneur collateral constraint integrating capital, real commercial estate and wage bill in advance is empirically relevant compared to the collateral literature associated to the labor market which does not consider these three assets. The second finding is the role of the housing price and credit squeezes in the rise of the unemployment rate during the Great Recession. The last two chapters have important implications for economic policy. A structural deregulation reform in the labor market induces a significant rise in the debt level for households and housing price, combined with a substantial rise of firm debt. Our approach allows us to reveal that a macroprudential policy aiming to tighten the LTV ratio for household borrowers has positive effects in the long run for output and employment, while tightening LTV ratios for entrepreneurs leads to the opposite effect.