The Shimer puzzle and the identification of productivity shocks

Shimer (2005) argues that the Mortensen-Pissarides (MP) model of unemployment lacks an amplification mechanism because it generates less than 10 percent of the observed business cycle fluctuations in unemployment given labor productivity shocks of plausible magnitude. This paper argues that part of the problem lies with the identification of productivity shocks. Because of the endogeneity of measured labor productivity, filtering out the trend component as in Shimer (2005) may not correctly identify the shocks driving unemployment. Using a New-Keynesian framework to control for the endogeneity of productivity, this paper estimates that the MP model can account for a third, and possibly as much as 60 percent, of fluctuations in labor market variables.Labor market ; Unemployment ; Labor productivity

Building a composite Help-Wanted Index over 1951-2009

This paper presents a measure of vacancy posting that captures the behavior of total --print and online-- help-wanted advertising. By modeling the share of online job advertising as the diffusion of a new technology --online job posting and job search-- I can combine information on both print and online help-wanted advertising. I use this consistent measure of vacancy posting over 1951-2009 to estimate the elasticity of the matching function and find an estimate of 0.58.Vacancy posting, help-wanted advertising, online, newspaper

The Shimer Puzzle and the Correct Identification of Productivity Shocks

Shimer (2005a) claims that the Mortensen-Pissarides search model of unemployment lacks an ampiflication mechanism because it cannot generate the observed business cycle fluctuations in unemployment given labor productivity shocks of plausible magnitude. This paper argues that part of the problem lies with the correct identification of productivity shocks. Because of the endogeneity of measured labor productivity, filtering out the trend component as in Shimer (2005a) may not correctly identify the shocks driving unemployment. Using a New- Keynesian framework with search unemployment, this paper estimates that close to 50% of the Shimer puzzle is due to the misidentification of productivity shocks. In addition, I show that extending the search model with an aggregate demand side remarkably improves the ability of the standard search model to match the moments of key labor market variables.unemployment fluctuations, labor productivity, search and matching model, New-Keynesian model

Productivity, Aggregate Demand and Unemployment Fluctuations

This paper presents new empirical evidence on the cyclical behavior of US unemployment that poses a challenge to standard search and matching models. The correlation between cyclical unemployment and the cyclical component of labor productivity switched sign at the beginning of the Great Moderation in the mid 80s: from negative it became positive, while standard search models imply a negative correlation. I argue that the inconsistency arises because search models do not allow output to be demand determined in the short run. I present a search model with nominal rigidities that can rationalize the empirical findings, and I document two new facts about the Great Moderation that can account for the large and swift increase in the unemployment-productivity correlation in the mid-80s.Unemployment Fluctuations, Labor productivity, Search and matching model, New-Keynesian model

Which industries are shifting the Beveridge curve?

The negative relationship between the unemployment rate and the job openings rate, known as the Beveridge curve, has been relatively stable in the U.S. over the last decade. Since the summer of 2009, however, the U.S. unemployment rate has hovered between 9.4 and 10.1 percent in spite of firms reporting more job openings. We decompose the recent deviation from the Beveridge curve into different parts using data from the Job Openings and Labor Turnover Survey (JOLTS). We find that most of the current deviation from the Beveridge curve can be attributed to a shortfall in the vacancy yield, which measures hires per vacancy. This shortfall is broad-based across all industries and is particularly pronounced in construction, transportation, trade, and utilities, and leisure and hospitality. Construction alone accounts for more than a third of the Beveridge curve gap.Unemployment ; Employment (Economic theory) ; Labor market

Which Industries Are Shifting the Beveridge Curve?

The negative relationship between the unemployment rate and the job openings rate, known as the Beveridge curve, has been relatively stable in the U.S. over the last decade. Since the summer of 2009, in spite of firms reporting more job openings, the U.S. unemployment rate has not declined in line with the Beveridge curve. We decompose the recent deviation from the Beveridge curve into different parts using data from the Job Openings and Labor Turnover Survey (JOLTS). We find that most of the current deviation from the Beveridge curve can be attributed to a shortfall in hires per vacancy. This shortfall is broad-based across all industries and is particularly pronounced in construction, transportation, trade, and utilities, and leisure and hospitality. Construction alone accounts for more than half of the Beveridge curve gap

Building a composite Help-Wanted Index over 1951-2009

This paper presents a measure of vacancy posting that captures the behavior of total --print and online-- help-wanted advertising. By modeling the share of online job advertising as the diffusion of a new technology --online job posting and job search-- I can combine information on both print and online help-wanted advertising. I use this consistent measure of vacancy posting over 1951-2009 to estimate the elasticity of the matching function and find an estimate of 0.58

Building a composite Help-Wanted Index over 1951-2009

This paper presents a measure of vacancy posting that captures the behavior of total --print and online-- help-wanted advertising. By modeling the share of online job advertising as the diffusion of a new technology --online job posting and job search-- I can combine information on both print and online help-wanted advertising. I use this consistent measure of vacancy posting over 1951-2009 to estimate the elasticity of the matching function and find an estimate of 0.58

Hydro-mechanical behaviour of compacted bentonite-sand mixture used as sealing materials in radioactive waste disposal

In order to verify of the geological high-level radioactive waste disposal, IRSN has undertaken the SEALEX research project to control the long-term performance of swelling clay-based sealing systems. Compacted bentonite-sand mixtures are one of the most appropriate sealing materials studied in this project because of its low permeability and good swelling capacity. Once installed, this material will be in contact with the host-rock pore water and start swelling to close all the gaps in the system (internal pores, rock fractures and technological voids) and then, swelling pressure develops. In parallel with the in-situ SEALEX project, laboratory experiments are performed to investigate the sealing properties under this complex hydro-mechanical condition taking into consideration the effect of technological voids. In this work, two approaches for this study are presented : one studies the sealing properties of the buffer as a homogeneous material, while the second distinguishes two states of the material : the compacted central part and the loose gel formation in the technological void following swelling