Essays in applied microeconomics.
详细信息
文摘
This dissertation is a collection of essays in the field of applied microeconomics that are focused on international trade and health. The first two chapters explore the applicability of the method put forth by Helpman, Melitz and Rubenstein (HMR) to extend the standard gravity model of trade when it is applied to the world trade data. First, I test the robustness of HMR methodology by splitting the world trade data into OECD and non-OECD countries. The extensive margin correction to the gravity model should be both economically and statistically more significant for the OECD exporters, while export selection should play a larger in the trade flows for the non-OECD exporters. I find that the extensive margin is not significant for the OECD trade flows, but the export selection is important regardless of the exporter location. I call this finding a "North-South" puzzle that I seek to resolve. In the second chapter, I shed light on this puzzle by decomposing the world trade data between three industries (manufacturing, mining and agriculture). The presumption is that the HMR correction should be most prominent for manufacturing trade and less so for the other industries. I confirm this prediction and find that using the trade data at an aggregate level confounds the significance of the extensive margin by mixing the industries. In addition, I show that there is an important relationship between the HMR correction and the upward bias in the gravity estimates: the upward bias is strong only when the extensive margin is a significant determinant of the trade flows. I set up industry level HMR framework to explain these findings. In my third chapter, I examine the effects of health insurance status on health outcomes for women age 17--21 during prenatal care and childbirth. I set up a quasi-experimental model that is driven by an abrupt change in insurance policy rule at age 19. Such shift allows for a regression discontinuity design, which essentially implies a using policy change as an instrument of health insurance coverage, thus solving insurance endogeneity problem that is found in prior research.