The role of technological change in labor market polarization has been subject to recent critique. This paper finds that changes in production technology played an important role in wage and job polarization in the US. It also demonstrates that such technological change is consistentwith the timing of labor market polarization in the US, including the stagnation of the 50/10 wage percentile ratio and the slowdown of employment growth in high-wage jobs from the 2000s. The paper does so using a model with two key ingredients: 1) directed search and 2) two-sided multi-dimensional heterogeneity. Estimation results show that the complementarity between cognitive skill and task increased while that between manual skill and task did not. The full model can fullyaccount for the rise and fall of the 90/50 and 50/10 wage percentile ratios respectively. It also generates 72.6 percent of the rise in employment share of high-paying jobs relative to middling jobs and 69 percent of the fall in employment share of middling jobs relative to low-paying jobs. The paper suggests that the stagnation of the 50/10 wage ratio may be due to rank-switching between workers across the wage distribution from the 2000s, while the slowdown of employment growthin high-wage jobs may result from the trade-off between the returns to applying for high-wage jobs and the likelihood of being hired.

This thesis examines the themes of sorting, inequality and the impact of technological change on the labor market. In particular, it addresses the questions of how workers sort within and between firms and how this influences labor market inequality, both in the workforce as a while, as well as between demographic and skill groups. It also considers how changes in technology affects the labor market conditions faced by workers and firms. These questions are tackled over three chapters. The first chapter, entitled `Multidimensional heterogeneity and matching in a frictional labor market - an application to polarization' deals with the sorting of workers to firms along multidimensional characteristics and quantifies the impact of technological change on the evolution of sorting patterns, wages and employment outcomes of different skill and demographic groups. I construct a model of directed search with two-sided multidimensional heterogeneity and estimate the model on US data. I find that production complementarities between cognitive and interpersonal skills and tasks have increased, relative to hat between manual skills and manual tasks. This change in production technology accounts for a large part of wage and job polarization in the US. Also, despite being gender-blind, the model can explain a substantial fraction of the narrowing of gender wage and job rank gaps from the 1980s to the present day. The second chapter, entitled `Intra-firm hierarchies and gender gaps' and coauthored with Nicolo Dalvit and Aseem Patel, studies the sorting of women into layers of hierarchy within firms, using administrative French data, and examines the incidence of gender wage and employment gaps across hierarchies over time. Further, by exploiting a policy on corporate board quotas in France, it assesses the impact of an increase in female leadership on gender wage and employment outcomes within firms. We find that hierarchies matter in gender wage and employment gaps. Gender wage and employment gaps increase with each layer of firm hierarchy, even if these gaps narrow more over time in the upper layers. In addition, improvements in top female leadership has differing impacts across hierarchies. While a greater share of female corporate board members narrows the gender wage gap in top layers of hierarchy, it has no such impact on lower layers. Instead, it increases the share of women in lower layers working part-time, at the expense of full-time employment. The opposite is true for women in upper layers. The third chapter, `Occupational Shortage and Labor Market Adjustments: a Theory of Islands', coauthored with Riccardo Zago, addresses the incidence of occupational shortage, and assesses whether it leads to wage and employment adjustments. Using a unique dataset on reported vacancies that firms find difficult to fill, we document the incidence of shortage across regions, industries and occupation groups. We find that shortage only leads to wage and employment adjustments in non-routine occupations, but not in routine occupations. We show how the secular decline of the routine occupations, caused by technological change, can account for the persistence in shortage in the routine sector and its inability to adjust.

In my thesis, I study the effects of agents' heterogeneity on labor market outcomes, with particular focus on sorting, performance, wages, and inequality. Chapter one studies multidimensional matching between workers and jobs. Workers differ in manual and cognitive skills and sort into jobs that demand different combinations of these two skills. To study this multidimensional sorting, I develop a theoretical framework that generalizes the unidimensional notion of assortative matching. I derive the equilibrium in closed form and use this explicit solution to study biased technological change. The key finding is that an increase in worker-job complementarities in cognitive relative to manual inputs leads to more pronounced sorting and wage inequality across cognitive relative to manual skills. This can trigger wage polarization and boost aggregate wage dispersion. I then estimate the model for the US during the 1990s. I identify a significant increase in complementarities of cognitive inputs and in cognitive skill-bias in production. Counterfactual exercises suggest that these technology shifts can account for observed changes in worker-job sorting, wage polarization and a significant part of the increase in US wage dispersion. Chapter two develops a theory that links differences in men's and women's social networks to disparities in their labor market performance. We are motivated by our empirical finding that men's and women's networks differ. Men have a higher degree (more network links) than women, but women have a higher clustering coefficient (a woman's friends are also friends among each other). In our model, a worker with a higher degree has better access to information. In turn, a worker with a higher clustering coefficient faces more peer pressure. Both peer pressure and access to information can attenuate a team moral hazard problem in the work place. But whether peer pressure or access to information is more important depends on the work environment. We find that, in environments where uncertainty is high, information is crucial and, therefore, men outperform women / in line with findings from sectors with high earnings' uncertainty like the financial or film industry.

The World of Work Report 2013 provides analyses the global employment situation five years after the start of the global financial crisis. It looks at labour market performance and projections both at the global and regional levels

This book is a welcome reassertion of an old tradition of interdisdplinary research. That tradition has tended to atrophy in the last decade, largely because of an enormous expansion of the domain of neoc1assical economics. The expansion has fed on two sdentific developments: first, human capital theory; second, contract theory. Both developments have taken phenomena critical to the operation of the economy but previously understood in terms of categories separate and distinct from those with which economists generally work and sought to apply the same analytical techniques that we use to understand other economic problems. Human capital theory has applied conventional techniques to questions of labor supply. It began this endeavor with the supply of trained labor and then expanded to a general theory of labor supply by broadening the analysis to the allocation of time over the individual's life, the interdependendes of supply decisions within the family, and finally to the formation of the family itself. Similarly, contract theory has moved from a theory that explains the existence of c10sed economic institutions to a theory of their formation and internaioperation. The hallmark of both of these developments is the extension and applica tion of analytical techniques based on purposive maximization under con traints and the interaction of individual decision makers through a com petitive market or its analogue.

Exploring a new agenda to improve outcomes for American workers As the United States continues to struggle with the impact of the devastating COVID-19 recession, policymakers have an opportunity to redress the competition problems in our labor markets. Making the right policy choices, however, requires a deep understanding of long-term, multidimensional problems. That will be solved only by looking to the failures and unrealized opportunities in anti-trust and labor law. For decades, competition in the U.S. labor market has declined, with the result that American workers have experienced slow wage growth and diminishing job quality. While sluggish productivity growth, rising globalization, and declining union representation are traditionally cited as factors for this historic imbalance in economic power, weak competition in the labor market is increasingly being recognized as a factor as well. This book by noted experts frames the legal and economic consequences of this imbalance and presents a series of urgently needed reforms of both labor and anti-trust laws to improve outcomes for American workers. These include higher wages, safer workplaces, increased ability to report labor violations, greater mobility, more opportunities for workers to build power, and overall better labor protections. Inequality in the Labor Market will interest anyone who cares about building a progressive economic agenda or who has a marked interest in labor policy. It also will appeal to anyone hoping to influence or anticipate the much-needed progressive agenda for the United States. The book's unusual scope provides prescriptions that, as Nobel Laureate Joseph Stiglitz notes in the introduction, map a path for rebalancing power, not just in our economy but in our democracy.