Xiao Ma

Ph.D. Candidate

Phone: (858) 500-2597

Email: xim032@ucsd.edu

Research Summary

I work on international trade and macroeconomics. My primary line of research combines micro-level data and structural models to study the interaction between trade, innovation, and human capital. Research Statement

Working Papers

College Expansion, Trade, and Innovation: Evidence from China Job Market Paper

This paper examines how China's expansion of college education since 1999 affects innovation and exports' skill content. I develop a two-country spatial equilibrium model, featuring skill intensity differences across industries and heterogeneous firms' innovation and exporting choices. I empirically validate my model mechanisms about how the college expansion affects innovation and exports, exploiting differential supply shocks of college-educated workers across regions due to historical college endowments. I apply the resulting reduced-form estimates in the calibration to discipline key elasticities that pin down export expansion strength. Under different assumptions about firm entry, I find that China's college expansion explained 40-70% of increases in China's manufacturing R&D intensity between 2003--2018 and triggered export skill upgrading. I also find that trade openness amplified the impact of this education policy change on China's innovation and production.

Human Capital Investment and Development: The Role of On-the-Job Training (with Alejandro Nakab and Daniela Vidart)

This paper examines how firm-training patterns differ across countries. We use enterprise surveys and worker surveys from 100 countries and show that the share of workers offered on-the-job training increases with development, and that employer-provided training is a key determinant of on-the-job human capital investments. We then build a general equilibrium search model with joint firms' and workers' decision on training investments to explore the importance of some key channels underlying the relationship between firm training and development. We find that self-employment is the main factor explaining the lack of on-the-job training in the poorest economies, and that labor market frictions become more relevant to explain training investments as countries develop. According to the model, on-the-job training accounts for a large share of the life cycle human capital accumulation patterns found in recent studies. Our model predicts considerable inefficiencies in human capital investments and sizeable aggregate gains from training subsidies to firms. We show that subsidies should be larger in developing economies where self-employment or job destruction is higher or when contract quality is lower.

China's Export Surge and the New Margins of Trade (with Chen Liu) Under Review

We build a multi-sector spatial general equilibrium model to account for China’s export surge between 1990 and 2005. We focus on the role of the reductions in tariffs and internal migration costs during that period. Our model generates a closed-form aggregate trade elasticity that can be decomposed into four margins of adjustments. Two are the commonly studied intensive and extensive margins of exports (Chaney, 2008). The remaining two margins are the new-firm margin and the export-regime margin, for which we have found empirical support and used our reduced-form evidence to discipline the structural parameters. Using the calibrated model, we find that the reductions in tariffs and internal migration costs accounted for a third of China’s export growth between 1990 and 2005. Among the four margins, we find that the new-firm margin played an important role in amplifying the effect of these policy changes on export growth.

Learning by Exporting and Wage Profiles: New Evidence from Brazil (with Alejandro Nakab)

This paper studies how exporting shapes experience-wage profiles. Using detailed Brazilian employer-employee and customs data, we document that workers' experience-wage profiles are steeper in exporters than in non-exporters. Aside from self-selection of firms with higher returns to experience into exporting, we show that workers' experience-wage profiles are steeper when firms export to industrialized destinations. We propose that this result is likely driven by faster human capital accumulation of workers in firms that export to advanced destinations. To support our preferred hypothesis, we use enterprise surveys and document that exporters are more likely to train workers than non-exporters, especially when they adopt foreign technology.

Comparative Advantage and Human Capital: A Cross-country Quantitative Analysis (with Alejandro Nakab)

Trade openness can affect welfare through changes in workers' skill acquisition. We develop a multisector Eaton--Kortum model, in which skill intensities and on-the-job learning opportunities are heterogeneous across sectors. Workers decide whether to become skilled before entering the labor market, and accumulate human capital on the job. Through the lens of our model, trade-induced sector reallocation changes the returns of becoming skilled and on-the-job learning opportunities. Our model allows for an analytical formula of the gains from trade. This formula is an augmented version of the ACR formula and includes gains due to changes in skill acquisition. Our calibrated model suggests that the gains from trade due to changes in skill acquisition are vastly different across countries and may be negative, with sizable gains for the United States, the United Kingdom, and India, as well as considerable losses for Germany, Brazil, and Argentina.

Selected Work in Progress

Comparative Advantage and Home Market Effects under Uncertainty (with Natalia Ramondo)

Global Value Chains and Natural Disasters (with Natalia Ramondo and Victoria Wenxin Xie)

Natural Disasters, Firm Entry, and Local Labor Markets (with Ruixue Jia and Victoria Wenxin Xie)

How do Workers Learn? Sources of Human Capital Accumulation within Firms (with Alejandro Nakab and Daniela Vidart)

Chinese Publications

''Debt-Deflation'' Risks and Coordination between Monetary and Fiscal Policies (with Xiaoliang Chen), Economic Research Journal (''经济研究''), 2016

Factor Price Distortions, Firm Investment, and Output (with Yanbin Chen and Zhexi Liu), The Journal of World Economy (''世界经济''), 2015