Theses Doctoral

Essays on International Trade, Welfare and Inequality

He, Zheli

How important are the distributional effects of international trade? This has been one of the most central questions pursued by international economists, particularly because much of the public opposition towards increased openness is due to the belief that welfare changes are unevenly distributed. In this dissertation, I rely on counterfactual analysis and natural experiments to study topics of international trade, welfare and inequality in the context of both developing and developed economies. In particular, I combine theoretical modeling and empirical analysis to examine the effects of international trade on (1) real wages of individuals within and across countries; (2) within-sector wage dispersion caused by heterogeneous responses of firms with different productivity levels to cheaper imported inputs.
In each of the three chapters, I contribute to the existing literature by relaxing simplifying assumptions that have proved to be inconsistent with data and exploring new mechanisms that link international trade to inequality.
Chapter 1, “Trade and Real Wages with Demand and Productivity Heterogeneity,” presents a general equilibrium model that incorporates the effects of trade liberalization on both an individual’s nominal wage and consumer price index. A vast majority of the literature focuses on the income channel, which is its effect on the distribution of nominal wages across workers. A small number of studies consider the expenditure channel, which is its differential impact on consumer price indices. It is well known that the consumption baskets of high-income and low-income consumers look very different. To our knowledge, there are only three case studies that have looked at these two channels jointly for individual countries, Argentina, Mexico and India. We provide a unified framework incorporating both channels by allowing for non-homothetic preferences and worker heterogeneity across jobs. In spite of its many dimensions of heterogeneity at the individual level, the model remains tractable enough that allows us to estimate its key parameters and perform counterfactuals.
Chapter 2, “Trade and Real Wage Inequality: Cross-Country Evidence,” addresses the following question: what is the impact of trade liberalization on the distribution of real wages in a large cross-section of countries? Trade liberalization affects real-wage inequality through two channels: the distribution of nominal wages across workers and, if the rich and the poor consume different bundles of goods, the distribution of price indices across consumers. Prior work has focused mostly on one or the other of these channels, but no paper has studied both jointly for a large set of countries. Based on the theoretical framework in Chapter 1, I measure the distributional effects of trade liberalization incorporating both channels for a sample of 40 countries. More specifically, I parametrize the model using sector-level trade and production data. Because skill-intensive goods are also high-income elastic in the data, I find an intuitive, previously unexplored, and strong interaction between the two channels. According to my counterfactual analysis, trade cost reductions generate dramatically different results for both nominal wage inequality and price index inequality than what previous research has obtained by focusing on either channel alone. I find that trade cost reductions decrease the relative nominal wage of the poor and the relative price index for the poor in all countries. On net, real-wage inequality falls everywhere.
Chapter 3, “Imported Inputs and Within-Sector Wage Dispersion,” proposes a new mechanism through which trade liberalization affects income inequality within a country: the use of imported inputs. Intuitively, a firm with higher initial productivity is better at using higher quality foreign inputs. This justifies paying the fixed costs for a larger set of imported inputs when input tariff liberalization decreases their relative price. The firm becomes more import intensive, which enhances its productivity advantage. As a result, the firm hires higher quality workers, produces higher quality products and pays higher wages to its workers, increasing within-sector wage dispersion. We find that both the mean and the dispersion of the distribution of firm productivity, markup and size went up during a period when China reduced its tariffs on imported inputs. More importantly, these results still hold when we consider the subset of firms that survived throughout the sample period, from 1998 to 2007. In addition, we develop a partial-equilibrium, heterogeneous-firm model with endogenous imported inputs and labor quality choice that is consistent with these observations. Finally, we provide empirical evidence that supports the model’s prediction that the differential change in the import intensity of firms with different productivity levels explains these patterns.


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More About This Work

Academic Units
Thesis Advisors
Weinstein, David E.
Ph.D., Columbia University
Published Here
August 8, 2017