Date of Award

Spring 5-15-2017

Author's School

Graduate School of Arts and Sciences

Author's Department


Degree Name

Doctor of Philosophy (PhD)

Degree Type



Chapter 1 proposes a new perspective to explain job polarization over the past few decades. Consisting of employment and wage polarization, job polarization is a widely documented phenomenon that involves the decline in both the employment shares and relative wages of middle-skill occupations with respect to high- and low-skill occupations. I present empirical evidence and build a task-based model demonstrating that job polarization stems from the interaction of the decrease in the relative price of capital goods, heterogeneity in job task production, and the complementarity of job tasks in final goods production. First, I construct a measure of occupation-level capital intensities and document that the tasks of middle-skill workers tend to be more capital intensive. Second, I build a task-based model with two goods sectors and three job tasks, where the job task production differs in capital intensity and how a worker's skill is utilized. The model shows that when there is a decrease in the price of capital goods, employment shifts away from capital-intensive tasks, and the relative wages are driven down, implying that decreasing price of capital goods predicts job polarization. A quantitative analysis suggests that the model can account for approximately one-third to one-half of the employment polarization and approximately half of the upper tail of the wage polarization in the U.S. between 1980 and 2010.Chapter 2 studies the endogenous formation of economic policies and its interplay with political institutions. Both the degree and the content of industrial policies are dispersed across countries. Some countries have active industrial policies while some do not. Among those with active industrial policies, some tend to target large conglomerates, while others target small and medium-sized enterprises (SMEs). This paper studies how the industrial policy in an economy is endogenously determined under a political economy framework with lobbying. Two political parties compete for votes in the election; the one that takes office will decide the industrial policy. The two parties announce policy platforms prior to the election, and voters make decisions based on their expected welfare but may be swayed by election campaigns depending on their political awareness. The campaign is financed by political donations, and its effectiveness is determined by the party's influence on mass media. Contingent on the political environment, the model can capture three major types of policy schemes: no active industrial policies, active pro-conglomerates policies, and active pro-SMEs policies.Chapter 3 studies the influence of employers' quality on growth when talents are imperfect information. I build an innovation choice model that differentiates two types of innovations: incremental and radical innovations; the former is a productivity improvement over an existing product line, and the latter, the construction of a new product line with superior productivity. The arrival rate of successful innovations depends on worker's human capital, while innovation choices are made by managers. Worker's human capital is imperfect information to managers--only high-type managers can distinguish the necessary human capital for radical innovations. The mass of high-type managers thus determines the distribution of innovation implementation and affects individuals' incentives to invest in human capital. Since incremental innovations are subject to diminishing returns while radical innovations create space for future incremental innovations, a society lacking consistent inflow of high-type managers will suffer from slower growth in the long run.


English (en)

Chair and Committee

Ping Wang

Committee Members

Costas Azariadis, Limor Golan, Yongseok Shin, David Wiczer,


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