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Working Papers


We show that the inability of a standardly-calibrated stochastic labor search-and matching model to account for the observed volatility of unemployment and vacancies extends beyond U.S. data to a set of OECD countries. We also argue that using cross-country data is helpful in evaluating the relative merits of the alternatives that have appeared in the literature. In illustrating this point, we take the solution proposed in Hagedorn and Manovskii (2008) and show that its ability to match the labor market volatility magnitudes seen in the data depends crucially on how persistent the estimated productivity process is.

"Search Frictions and the Labor Wedge” with Andrea Pescatori (NEW - Significantly Updated version of the old WP!)

We show that search frictions embedded in a RBC model primarily manifest themselves at the extensive margin. The ability to distinguish between intensive and extensive margin, however, affects the measurement of the marginal rate of substitution (MRS). In fact, the correct measurement of the MRS, in terms of hours per worker, implies a less variable and procyclical labor wedge than the one found in Chari et. al. (2007), especially at low Frisch elasticity. The main result is very robust to alternative wage determination mechanisms, even though implications for employment fluctuations may differ.

(PRIOR VERSION - April 2011)

Forthcoming in Macroeconomic Dynamics.

We construct a multiple shock, discrete time version of the Mortensen-Pissarides labor market search model to investigate the basic model's well-known tendency to underpredict the volatility of key labor market variables. In addition to the standard labor productivity shock, we introduce shocks to matching efficiency and job separation. We conduct two set of experiments. First, we estimate the joint probability distribution of shocks that simultaneously satisfy the observed data and the first-order conditions of the multiple-shock model, and then simulate its properties. Although the multiple-shock model generates significantly more volatility while preserving the Beveridge curve relationship, it generates counterfactual implications for the cyclicality of job separations. Using a business cycle accounting approach, we design the second set of experiments to isolate the sources of model incompleteness and show that the model requires significant procyclical and volatile matching efficiency and counterfactually procyclical job separations to render the observed data without error. We conjecture that the basic Mortensen-Pissarides model lacks mechanisms to generate sufficiently strong labor market reallocation over the business cycle, and suggest nontrivial labor force participation and job-to-job transitions as promising avenues of research.

(PRIOR VERSION - May 2011)

"The Ins and Outs of Unemployment in the Long Run: Unemployment Flows and the Natural Rate" (NEW - Substantially revised version of the older working paper !)

This paper proposes an empirical method for estimating a long-run trend for the unemployment rate that is grounded in the modern theory of unemployment. I write down an unobserved components model and identify the cyclical and trend components of the underlying unemployment flows, which in turn imply a time varying estimate of the unemployment trend, the natural rate. I identify a sharp decline in the outflow rate - job finding rate- since 2000, which was partly offset by the secular decline in the inflow rate -- separation rate -- since 1980s, implying a relatively stable natural rate, currently at 6 percent. Numerical examples show that slower labor reallocation along with the weak output growth explains most of the persistence in unemployment since the Great Recession. Contrary to the business-cycle movements of the unemployment rate, a significant fraction of the low-frequency variation can be accounted for by changes in the trend of the inflows, especially prior to 1985. Finally, I highlight several desirable features of this natural rate concept that makes it a better measure than traditional counterparts. These include statistical precision, the significance of required revisions to past estimates with subsequent data additions, policy relevance and its tight link with the theory.

(PRIOR VERSION - August 2011)


  We review the positive and normative effects of a minimum wage in various versions of a search-theoretic model of the labor market.

This paper studies amplification of productivity shocks in labor markets through on-the-job-search. There is incomplete information about the quality of the employee-firm match which provides persistence in employment relationships and the rationale for on-the-job search. Amplification arises because productivity changes not only affect firms' probability of contacting unemployed workers but also of contacting already employed workers. Since higher productivity raises the value of all matches, even low quality matches become productive enough to survive in expansions. Therefore the measure of workers in low quality matches is greater when productivity is high, implying a higher probability of switching to another match. In other words, firms are more likely to meet employed workers in expansions and those they meet are more likely to accept firm's job offer because they are more likely to be employed in a low quality match. This introduces strongly procyclical labor market reallocation through procyclical job-to-job transitions. Simulations with a productivity process that is consistent with average labor productivity in the U.S. show that standard deviations for unemployment, vacancies and market tightness (vacancy-unemployment ratio) match the U.S. data. The model also reconciles the presence of endogenous separation with the negative correlation of unemployment and vacancies over business cycle frequencies (i.e. it is consistent with the Beveridge curve).