Browsing by Author "Chen, Susan Elizabeth"
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- Essays On Health EconomicsPilehvari, Asal (Virginia Tech, 2021-02-10)This dissertation consists of three essays in Health Economics relating to the recent challenges in the U.S. The first essay studies the impact of retirement on subsequent health and investigates the mediation effect of social network in the relationship between retirement and health. Findings reveal that retirement adversely impacts physical and mental health outcomes and a considerable portion of these effects are explained by social network changes post-retirement. In particular, shrinkage in the size of social network post-retirement deteriorates physical health and increases depression in retirees. In the second essay, we assess the differential effect of social distancing on the daily growth rate of COVID-19 infections in the US counties by considering the spatial pattern of COVID-19 spread. We also conduct a comparative analysis of the effect on urban versus rural counties, as well as low versus high socially vulnerable counties. Our analysis illustrates that a high level of social distancing compliance is needed in urban counties and in socially vulnerable areas to achieve the largest impact at curve flattening, whereas moderate-compliance is enough in reaching the peak marginal impact in rural regions and counties with low social vulnerability. In the third essay, by combining multiple data sources, we investigate how racial disparities in access to healthcare contribute to the disparity in COVID-19 infections and mortality in black versus white sub-groups. The multilevel analysis demonstrates that a higher probability of having health insurance significantly reduces disparity in COVID-19 mortality in black sub-group while it has no impact on the disparity in whites.
- Essays on Price and Time in Trade and Household ProductionYang, Jinyang (Virginia Tech, 2022-07-13)This dissertation consists of three chapters that estimate the elasticities regarding price and time in trade and household production. Chapters 1 and 2 estimate price elasticities. Chapter 1 estimates the one-factor-one-price elasticity of substitution (OOES)—or how the percentage change in the quantity of one good responds to the percentage change in the price (of itself or another good)—in an international trade context. Chapter 2 estimates the two-factor-one-price elasticity of substitution (TOES)—or the difference of percentage changes between two quantities with respect to the percentage change in the price of one good—in the context of household food production. Chapter 3 estimates the elasticity of export quantity and value with respect to delays in the time it takes to load or unload products at US ports. Chapter 1 estimates the price elasticities in agricultural trade. Armington elasticities, the elasticity of substitution between goods from different countries, are key parameters in agricultural trade policy evaluation and welfare calculation. We estimate Armington elasticities for a selected basket of 38 agricultural commodities in 5 categories by compiling a sample of 118 countries' production and trade flows. Following and extending Feenstra et al. (2018), we estimate both the micro-elasticity of substitution between foreign sources of imports and the macro-elasticity of substitution between home and imported products at the commodity level. The median of the micro- and macro-elasticities are 6.4 and 5.0, respectively. Meat products have the lowest micro- and macro-elasticities, with the micro-elasticities ranging from 4.2 (pork) to 5.0 (poultry) and the macro-elasticities ranging from 2.9 (pork) to 4.5 (beef). Crops products have the widest range of Armington elasticities, with micro-elasticities ranging from 2.5 (pigeon peas) to 90.3 (peanuts), and macro-elasticities ranging from 1.2 (pigeon peas) to 20.1 (peanuts). In line with the literature, we find that 75 percent of the agricultural commodities have numerically smaller macro-elasticities than micro-elasticities, even though only 6 of them (pork, poultry, corn, peanuts, apples, and peppers) are statistically smaller at the 5 percent level. We explore the robustness of our estimates by slicing the sample into separate periods and importing countries. Finally, we discuss the policy implications of our estimates on predicting trade due to tariff changes and understanding welfare gains from agricultural trade. Chapter 2 estimates the goods-time elasticity of substitution (EOS), the responsiveness of the difference between money and time in household production for change of opportunity cost of time (OCT). This chapter bridges the gap between literature that directly and indirectly estimates the goods-time EOS in household production. Inspired by the studies in environmental economics, we argue the opportunity cost of time in household production not only depends on wage but life-cycle dynamics and household demographics as well. We proceed with the estimation by two strategies: direct estimation of the household production, and the demand-supply approach borrowed from Feenstra's (1994) research on trade elasticities. Both strategies report the estimates are much larger than unit and closer to previous indirect estimates. We show our results are robust when applied to Aguiar and Hurst's (2007) sample, in which they employed the indirect estimation. The larger goods-time EOS indicates policies aiding households with money for groceries like the Supplemental Nutrition Assistance Program (SNAP) are more sufficient, since money for certain groceries can more easily substitute for time in making meals. Chapter 3 explores the elasticity of trade with respect to port congestion time. U.S. ports have struggled with significant supply chain congestion during the past two years. Anecdotal evidence shows the increasing port congestion brought substantial losses to U.S. exports, particularly agricultural shipments. However, previous studies are limited by the availability of explicit data on congestion times for unloading. This study first quantifies the association between port congestion days and U.S. agricultural exports, using monthly export data of top U.S. ports and their monthly average container and bulk shipments delays. We find one extra day delay of container shipments decreases U.S. agricultural monthly exports by 5 percent in quantity or 2 percent in value on average. That amounts to $63 million in monthly loss of export value on average, and Western U.S. ports are responsible for 69 percent of this total. The effect is most pronounced for the Western U.S. exports of bulk commodities, where congestion results in a 9 percent loss in quantity or 8 percent loss in value. For Eastern U.S., the most salient effect is on consumer commodities, with a loss of 3 percent in quantity and 3 percent in value. For the Gulf region, the largest effect is on bulk commodities, with a loss of 4 percent in quantity and 5 percent in value. The impacts of congestion on bulk shipments are both statistically and economically insignificant. However, we find some evidence that exporters substitute bulk cargoes with containers when bulk shipment delays at ports increase. The substitution of container shipments with bulk shipments, however, is unlikely.
- Essays on Social Capital and Peer EffectsJiang, He (Virginia Tech, 2022-06-03)In Chapter 2, I employ the educational production function to identify the different effects of making a friend of the same gender and the opposite gender in a school network. Unlike other gender peer effects literature that only quantifies the causal effects of the proportion of girls in an aggregated level, such as other students in the same class, grade, or dorm, I study the gender of the five best friends nominated by the student. I address the endogeneity of friendship composition by employing a novel set of instrumental variables for the number of same-gender and opposite-gender friends. We find that having more friends, especially in the early accumulation stage, lowers the test scores. We also explore the mechanisms. In Chapter 3, I investigate the role of social learning in enrollment decisions for a public pension scheme. All else equal, if a qualified rural resident moves from a community where no other co- villagers participate in the new pension scheme to a community that is fully covered by the pension scheme, the probability of an individual enrolling by 0.541 percentage point. We use robustness checks to illustrate that the estimated peer effects are not driven by the common unobserved factors, but by social interactions. In Chapter 4, we use the survey data on Chinese middle students and the instrumental variables method to explore the different effects of making friends with the same gender and the opposite gender in a school network on mental health. The empirical results find that having a larger number of same-gender friends improves mental health but having a larger number of opposite-gender friends hurts mental health.
- Human Capital in Appalachia: An Analysis of Vulnerability, Resilience, and Skills in Preparation of a Greener EconomyPierce, Timothy Samuel (Virginia Tech, 2022-09-08)This thesis constructs a novel resilience index and a comparative advantage measure of professional skills to enhance our understanding of economic resilience in Appalachian counties that are vulnerable to the transition to a greener economy. The index-based results indicate that resilience is clustered throughout the region and strongly related to local labor market demand for the skills required to complete non-routine cognitive tasks. Resilient labor markets hold a comparative advantage over their less resilient counterparts in twelve skills. These skills are highly prevalent in growing and emerging occupations and strongly related to resilience in the existing literature on regional economic shocks. This thesis also develops a database that enables future researchers, policymakers, and industry leaders to geospatially analyze skill prevalence at a county level and make informed and proactive decisions in the face of a changing economy.
- Land Use on the Urban FringeRippley, Samantha (Virginia Tech, 2023-06-30)Due to their location on the urban fringe, many historically agricultural counties face development pressure from a spreading urban core. These local communities must contend with often conflicting objectives of providing economic development opportunities while at the same time protecting their county's natural resources. Land conservation policies incentivize landowners to keep land identified as critical environmental resources in their natural state. In this project, we analyze property-level administrative data to evaluate whether land conservation policies and neighbor land use patterns affect the probability of land parcel development. We find some evidence of the contagion effect and that the county's acknowledgment of Priority Conservation areas impacts development motivation.