Research

Abstract: To what extent is a worker’s human capital growth affected by the quality of his coworkers? To answer this question, we develop and estimate a model in which the productivity and the human capital growth of an individual depend on the average human capital of his coworkers. The measured production function is supermodular: The marginal product of a more knowledgeable individual is increasing in the human capital of his coworkers. The measured human capital accumulation function is convex: An individual’s human capital growth is increasing in coworkers’ human capital only when paired with more knowledgeable coworkers, but independent of coworkers’ human capital when paired with less knowledgeable coworkers. Learning from coworkers accounts for two thirds of the stock of human capital accumulated on the job. Technological changes that increase production supermodularity lead to labor market segregation and, by reducing the opportunities for low human capital workers to learn from better coworkers, lead to a decline in aggregate human capital and output.

Abstract: We construct a structural model of on-the-job search in which workers differ in skills along several dimensions and sort themselves into jobs with heterogeneous skill requirements along those same dimensions. Skills are accumulated when used, and depreciate when not used. We estimate the model combining data from O*NET with the NLSY79. We use the model to shed light on the origins and costs of mismatch along heterogeneous skill dimensions. We highlight the deficiencies of relying on a unidimensional model of skill when decomposing the sources of variation in the value of lifetime output between initial conditions and career shocks.

Abstract: In this paper, we analyze the dynamics of intra-household allocations using unique panel data on individual-specific consumption expenditures and time used for leisure, market production and home production. Cross sectional differences at the time of marriage in expected wage profiles between a husband and wife strongly affect the allocation of private consumption expenditures and time use by households in the cross section. There are substantial gender asymmetries in these allocations. Even for households where the husband and wife have identical wages, the private consumption expenditures for the wife are about half those for the husband. Within a given household overtime, shocks to wages lead households to shift the relative weights in favor of the spouse receiving the favorable shock. Additionally we find that households adjust the weights in response to large but not to small shocks; the adjustment to the weights is twice as large in the year leading up to a divorce; and adjustments are more frequent in dual- than in single-earner households. We interpret the data using a dynamic collective model of the household with potentially limited commitment.

Abstract: We develop an equilibrium model of on-the-job search with ex-ante heterogeneous workers and firms, aggregate uncertainty and vacancy creation. The model produces rich dynamics in which the distributions of unemployed workers, vacancies and worker-firm matches evolve stochastically over time. We prove that the surplus function, which fully characterizes the match value and the mobility decision of workers, does not depend on these distributions. This result means the model is tractable and can be estimated. We illustrate the quantitative implications of the model by fitting to US aggregate labor market data from 1951-2012. The model has rich implications for the cyclical dynamics of the distribution of skills of the unemployed, the distribution of types of vacancies posted, and sorting between heterogeneous workers and firms.

Abstract: We develop an empirical search-matching model which is suitable for analyzing the wage, employment and welfare impact of regulation in a labor market with heterogeneous workers and jobs. To achieve this we develop an equilibrium model of wage determination and employment which extends the current literature on equilibrium wage determination with matching and provides a bridge between some of the most prominent macro models and microeconometric research. The model incorporates productivity shocks, long-term contracts, on-the-job search and counter-offers. Importantly, the model allows for the possibility of assortative matching between workers and jobs due to complementarities between worker and job characteristics. We use the model to estimate the potential gain from optimal regulation and we consider the potential gains and redistributive impacts from optimal unemployment benefit policy. Here optimal policy is defined as that which maximizes total output and home production, accounting for the various constraints that arise from search frictions. The model is estimated on the NLSY using the method of moments. 

Abstract: This paper introduces an innovative test of search and matching models using the exogenous variation available in experimental data. We take an off-the-shelf search model and calibrate it to data on the control group from a randomized social experiment. We then simulate a program group from a randomized experiment within the model. As a measure of the performance of the model, we compare the outcomes of the program groups from the model and from the randomized experiment. We illustrate our methodology using the Canadian Self-Sufficiency Project (SSP), a social experiment providing a time-limited earnings supplement for Income Assistance recipients who obtain full-time employment within a 12-month period. We find two features of the model are consistent with the experimental results: endogenous search intensity and exogenous job destruction. We find mixed evidence in support of the assumption of fixed hours of labor supply. Finally, we find a constant job destruction rate is not consistent with the experimental data in this context.

Abstract: In this paper we document the main features of the distributions of wages, earnings, consumption and wealth in Japan since the early 1980s using four main data sources: the Basic Survey on Wage Structure (BSWS), the Family Income and Expenditure Survey (FIES), the National Survey of Family Income and Expenditure (NSFIE) and the Japanese Panel Survey of Consumers (JPSC). We present an empirical analysis of inequality that specifically considers the path from individual wages and earnings, to household earnings, after-tax income, and finally consumption. We find that household earnings inequality rose substantially over this period. This rise is made up of two distinct episodes: from 1981 to 1996 all incomes rose, but they rose faster at higher percentiles; from 1996 to 2008 incomes above the 50th percentile remained flat but they fell at and below the 50th percentile. Inequality in disposable income and in consumption also rose over this period but to a lesser extent, suggesting taxes and transfers as well as insurance channels available to households helped to insulate household consumption from shocks to wages. We find the same pattern in inequality trends when we look over the life cycle of households as we do over time in the economy. Additionally we find that there are notable differences in the inequality trends for wages and hours between men and women over this period.

Abstract: In this article, I develop and estimate a model of on-the-job search in which risk averse workers choose search effort and can borrow or save using a single risk free asset. I derive the implications for optimal savings behavior in this environment and relate this to the frictions that characterize the endogenous earnings process implied by on-the-job search. Savings behavior depends in a very intuitive way on the rate at which offers are received, the rate at which jobs are destroyed, and a worker's current rank in the wage distribution. The implication is that workers, who are identical in terms of preferences and opportunities, have substantially different savings behavior depending on their history and current position in the wage distribution. The mechanism that generates the substantial differences in savings behavior in the model is the dynamic of the “wage ladder” resulting from the search process. There is an important asymmetry between the incremental wage increases generated by on-the-job search (climbing the ladder) and the drop in income associated with job loss (falling off the ladder). The behavior of workers in low paying jobs is primarily governed by the expectation of wage growth, while the behavior of workers near the top of the distribution is driven by the possibility of job loss. The distributions of earnings, wealth, and consumption implied by the model (suitably aggregated) align reasonably well with the data, with the notable exception of implying substantially less concentration of wealth among the richest one percent of the population.

Abstract: The consumption literature uses adult equivalence scales to measure individual-level inequality. This practice imposes the assumption that there is no within-household inequality. In this paper, we show that ignoring consumption inequality within households produces misleading estimates of inequality along two dimensions. To illustrate this point, we use a collective model of household behavior to estimate consumption inequality in the U.K. from 1968 to 2001. First, the use of adult equivalence scales underestimates the initial level of cross-sectional consumption inequality by 50%, as large differences in the earnings of husbands and wives translate into large differences in consumption allocations within households. Second, we estimate the rise in between-household inequality has been accompanied by an offsetting reduction in within-household inequality. Our findings also indicate that increases in marital sorting on wages and hours worked can simultaneously explain two-thirds of the decline in within-household inequality and between a quarter and one-half of the rise in between-household inequality for one and two adult households.

Abstract: We present new evidence on the labor market effects of large minimum wage increases by examining the policy changes implemented by Minneapolis and Saint Paul. Using synthetic difference-in-differences methods, we find that the minimum wage did not affect employment in most industries but decreased substantially restaurants’ employment. Next, using variation in exposure to the minimum wage across establishments and workers within zip codes and industries of the Twin Cities, we find employment effects that are half as large as those from the time series. The cross-sectional estimates difference out employment effects from the pandemic or civil unrest that could confound the time series comparisons, but they do not include equilibrium effects induced by the minimum wage such as changes in entry. We quantify a model of establishment dynamics to reconcile the different estimates and argue that they plausibly reflect lower and upper bounds of employment losses. We use the model to show that our estimates are consistent with an establishment elasticity of labor demand of −1 and illustrate how they can inform deeper parameters characterizing product and labor market competition, factor substitution, and establishment dynamics.

We develop non-parametric identification of models with two-sided heterogeneity, production complementarities, on-the-job search and job creation.  We estimate the model on matched employer-employee data from Sweden.

We revisit the evidence on the employment effects of the Americans with Disabilities Act. Contrary to the existing literature that has focused on individuals who face limitations related to their ability to work (work limitations), we assess the impact of the policy using data from the Survey of Income and Program Participation that allow us to distinguish among individuals with limitations related to their ability to work and individuals with other types of limitations (functional limitations). As consistent with the literature, we find that the policy has had a negative effect on the employment of individuals with work limitations, thus confirming and extending the existing evidence to a more recent time period. But we also find that the policy has had a substantial and significant positive effect on the employment of individuals with physical or mental limitations that are not work related, even when severe. We develop a search and matching model of the labor market in which a worker's productivity varies with a worker's health to rationalize and evaluate the heterogeneous impacts of the policy on the employment of disabled and non-disabled workers. 

We extend Lise and Robin (2017) to analyze the evolution of the wage distribution in response to aggregate shocks.

We develop a dynamic model to analyses the effects of labor policies, such as the minimum wage, across the skill distribution and over the business cycle.

A frictional model of the labor market with stochastic human capital accumulation and incomplete markets.  We provide a decomposition of life-cycle inequality in earnings and consumption resulting from heterogeneity in ability, heterogeneity in the rate of human capital accumulation, search frictions and the interaction of human capital and search frictions. 

We provide new and convincing evidence on the presence and magnitude of feedback effects associated with "make work pay" policies currently under consideration in the US, Canada, the UK and other developed countries using a general equilibrium model of the labor market.  

This is the first of four reports prepared for the City of Minneapolis, funded through the Federal Reserve Bank of Minneapolis. 

A non-technical summary of my recent work.