时间：2020年10月30日（周五）下午14:00 – 16:00
地点：浙江大学紫金港校区公管学院大楼112
题目一：The impact of internet use on adolescent learning outcomes: evidence from rural China
报告人：李丽莉，博士生
摘要：
Internet use has become particularly prevalent among adolescents, prompting much thought and concern about both its potential benefits and adverse effects on adolescent learning outcomes. Much of the empirical literature on the impact of internet use on adolescent learning outcomes is mixed, and few studies examine the causal relationship between the two. Few studies also use nationally representative longitudinal data to study the relationship between internet use and learning outcomes. In order to bridge these gaps in the literature, in this study we use fixed effect models with samples drawn from a large nationally representative dataset (the China Family Panel Studies—CFPS) to identify the causal impacts of internet use on the learning outcomes of three cohorts (Cohort A (N = 540), Cohort B (N = 287) and Cohort C (N = 827)) of adolescents in rural China. The results of the descriptive analysis show a continued increase in the number of adolescents accessing the internet and the amount of time they spend online. The results of the fixed effect models show that internet use has positive (in many of the analyses), but mostly insignificant impacts, on the learning outcomes of adolescents. In the sets of results that find significant associations between internet use and learning outcomes, the measured effects are moderate. According to the overall findings, we conclude that although internet access and usage is becoming more common among adolescents in rural China, there is not a great need to worry about adverse effects on adolescent learning development. Attention, however, should focused on seeking ways to improve the positive effects of the internet use on adolescent learning outcomes.
题目二：Do Farmers Gain Internet Dividends from E-commerce Adoption? Evidence from China
报告人：李晓康，博士生
摘要：
This study examines the effects of e-commerce adoption on household income, using survey data of 1,030 households in China. The combination of propensity score matching and difference-in-difference method is employed to address the sample selection bias associated with e-commerce adoption. The results show that e-commerce adopters obtain significantly higher income than non-adopters, and such a significant and large income gain is contributed by the significant increases in sales income and property income. E-commerce adoption has a significant and negative impact on wage income due to the labor substitution effect, while it affects transfer income insignificantly. Additional analysis reveals that the income effects of e-commerce adoption are heterogeneous across geographic locations and household-level characteristics.
题目三：政策干预、贸易成本与国内外粮食市场整合
报告人：王文亭，博士生
摘要：
本文利用2002年1月至2018年12月的月度时间序列数据，基于非线性门阈模型识别了大米、小麦、玉米和大豆的国际贸易成本，并构建了结构变动下的时变阈值模型，从贸易成本和价格调整两个方面，实证分析了入世以来中国粮食市场政策干预对国内外市场整合的影响。结果表明，国内外粮价存在显著的阈值效应；最低收购价政策和临时收储政策均显著提高了贸易成本，降低了国内粮价向均衡调整的速度。而在玉米、大豆取消临时收储政策后，国内外市场整合程度明显提高。以价格支持为主的粮食市场政策干预通过扭曲套利空间，降低了国内外市场整合程度，在统筹利用国际国内两个市场两种资源的过程中造成了效率损失。未来应在产、需与进口三元均衡的视角下重新审视我国的粮食安全问题，纠正对粮价的过度干预，推动国内外市场整合，提高国际市场与国际资源的利用效率。
