北大经院工作坊第1151场
Talk 1：Learning it Sooner or Later
Talk 2：Disclosure and Manipulation in Reputation System
微观理论经济学工作坊
主持老师：
（北大经院）吴泽南、石凡奇
（北大国发院）胡岠
参与老师：
（北大经院）胡涛
（北大国发院）汪浩、邢亦青
（北大光华）翁翕、刘烁
时间：2025年9月25日（周四）10:30-12:00
地点：北京大学经济学院302会议室
Talk 1
题目：Learning it Sooner or Later
主讲人：姜渭（北京大学光华管理学院）
主讲人简介：
Wei Jiang is a Ph.D. candidate of economics at Guanghua School of Management, Peking University. His research interests include learning theory, social network and search theory.
摘要：
Suppose a present-biased agent can perform a task at any period before the deadline but she is uncertain about the consequence if the task is not completed. We study the information design problem where a principal, who wants to maximize the long-run welfare of the agent, can commit a rule to dynamically disclose information about the consequence. We show that the optimal rule always features ``learning it sooner or never'' --- information is disclosed only at the first period. When the agent has more periods to perform the task, more information will be disclosed. Such optimal rule can be implemented by a sequential persuasion game where at each period, the agent can only commit the information structure for the next period. Our results are robust to the payoff structure with immediate rewards and delayed costs.
Talk 2
题目：Disclosure and Manipulation in Reputation System
主讲人：王禛阳（北京大学光华管理学院）
主讲人简介：
Zhenyang Wang is a Ph.D. candidate of economics at Guanghua School of Management, Peking University.
摘要：
Online reputation systems integrate soft information (ratings) and hard information (reviews) to mitigate information asymmetry in e-commerce markets, yet remain vulnerable to strategic manipulation by sellers. While the extant literature primarily examines these feedback mechanisms and their manipulation in isolation, the welfare implications of manipulation in joint systems that combine both channels remain theoretically underexplored. We develop a game-theoretic model to analyze three feedback system designs: rating-only, review-only, and joint feedback systems, both with and without seller manipulation. Our analysis yields a counterintuitive result: in a joint system, permitting simultaneous manipulation of both ratings and reviews can generate higher consumer welfare than prohibiting manipulation entirely or restricting it to only one channel. These findings challenge the prevailing view that manipulation uniformly reduces welfare and provide novel insights for platform governance, suggesting that optimal reputation system policies must consider the endogenous interactions between different feedback mechanisms.
北大经院工作坊第1152场
Evolution of Local Government Equity Assets in China: A New Measure Based on Equity Networks（中国地方政府股权资产演变：基于股权网络的新测度）
宏观经济学工作坊
主讲人：刘岩（中山大学商学院（创业学院）副教授）
主持老师：（北大经院）韩晗
参与老师：
（北大国发院）赵波、余昌华、李明浩
（北大经院）陈仪、李博、李伦
时间：2025年9月26日（周五）10:30-12:00
地点：北京大学国家发展研究院承泽园131教室
主讲人简介：
刘岩，中山大学商学院（创业学院）副教授。主要研究领域为宏观经济学、金融中介理论、货币银行学、公司金融，主持“中国银行业数据库（CBD）”项目，主持国家自科面上项目、青年项目，作为子课题负责人或主要人员参与多项国家社科重大项目、国家自科重点项目、科技部重点研发计划项目。在《人民日报·内参》《经济研究》、Review of Economic Studies、Journal of International Economics等国内外期刊发表论文近30篇。获得2020年首届PwC3535年度最佳论文奖，并两次获得中国金融学年会最佳论文奖。
摘要：
Measuring the equity assets of the government is crucial for assessing the financial stability and fiscal sustainability of the public sector. Using a novel business registration dataset of China, we propose a new measure of local government equity assets based on equity networks. Stylized facts indicate that the scale of equity assets decreases with administrative hierarchy. Furthermore, the dynamics trends show that the equity assets scales of local governments at various levels exhibit similar growth trends—steadily increasing before 2015, and experiencing higher growth rates thereafter. We use the implementation of real estate loan concentration management in 2020 as an exogenous shock to empirically explain the rapid expansion of equity assets between 2020 and 2022. Our study finds that prefectures more heavily impacted by this shock are more likely to engage in land acquisitions through LGFVs, thereby capitalizing land and leading to a sharp increase in equity assets.
北大经院工作坊第1153场
Marine Microplastics and Infant Health
经院-全健院
“健康与劳动经济学”工作坊
主讲人: Eric Zou（University of Michigan and NBER）
主持人: （北大全健院）潘聿航
参与老师：
（北大经院）秦雪征、施新政、石菊、姚奕、袁野、王耀璟、梁远宁、庄晨
（北大全健院）刘国恩、黄成、孙宇、吕蓓妮、崔知涵、林淑君、林昊翔、杨佳楠、蒋少翔
时间：2025年9月26日（周五）10:00-11:30
形式: Zoom会议
会议号: 844 8118 6335
密码: 559125
主讲人简介:
Eric Zou is an Assistant Professor of Business Economics and Public Policy at the Stephen M. Ross School of Business, University of Michigan, and a Faculty Research Fellow at the National Bureau of Economic Research. Zou studies the economics of pollution prevention. His current work focuses on emerging sources of pollution, evaluates their impacts on human and ecosystem health, and explores regulatory and consumer technology solutions. His research has been published in leading economics journals including The American Economic Review and The Review of Economics and Statistics, as well as general science and medical journals such as the PNAS and JAMA Internal Medicine. His research has been covered by popular media including The New York Times, The Economist, and other international media outlets. Prior to his Michigan appointment, Zou was an Assistant Professor at the University of Oregon, and a postdoctoral fellow at Cornell University. Zou received his Ph.D. in Economics from the University of Illinois at Urbana-Champaign, and holds a B.S. in Economics from East China Normal University.
摘要:
A century of plastic usage has led to an accumulation of plastic waste in waterways and oceans. Over time, these wastes break down into particles smaller than 5 microns or ”microplastics”–which can infiltrate human biological systems. Despite decades of research into this emerging source of environmental pollution, there is a lack of direct evidence on the health impacts of microplastics exposure at a population scale. This paper reports the first causal link between in-utero microplastic exposure and adverse birth outcomes. Our analysis is based on a compiled dataset of 3 million births that occurred in coastal areas of 15 countries spanning four continents, which we merge with a novel remote-sensing measurement of marine microplastic concentrations. We show that in-utero exposure to microplastics, particularly during the third trimester of pregnancy, leads to a significant increase in the likelihood of low birth weight. A doubling of exposure increases low birth weight hazard by 0.37 per 1,000 births, which implies over 205,000 cases per year globally can be attributed to microplastic exposure. We further show that aerosolization–whereby microplastic particles become airborne and inhalable due to seawater evaporation–is an important pathway for health impact, a challenge that is likely to escalate as ocean temperatures continue to rise.
北大经院工作坊第1154场
When Walls Becomes Targets: Strategic Speculation and Price Dynamics under Price Limit
计量、金融和大数据分析工作坊
主讲人：黎新平（北京大学经济学院研究员）
主持老师：（北大经院）王一鸣、王熙
参与老师：（北大经院）刘蕴霆、王法、巩爱博
时间：2025年9月26日（周五）10:00-11:30
地点：北京大学经济学院107会议室
主讲人简介：
黎新平，北京大学经济学院研究员、北京大学金融工程实验室执行主任，斯坦福大学经济学博士，主要研究方向为量化投资、资产定价、机器学习及人工智能技术在金融中的应用。曾在国际货币基金组织从事新兴市场贷款计划定价的研究，并在美国纽约大型对冲基金任资深策略师和投资经理，国内公募基金任量化投委会主席、量化投资总监及基金经理。
摘要：
This study shows how price limit rules, intended to stabilize markets, inadvertently distort price dynamics by fostering strategic speculation. Through a dynamic rational expectations model, we demonstrate that price limits induce inherent post limit-up price-jumps by impeding full information incorporation, motivating speculators to artificially push prices to upper bound and exploit uninformed traders. The model predicts two distinct patterns: (1) stocks closing at upper price limits exhibit positive overnight returns followed by long-term reversals, and (2) stocks retreating from upper bound before market close incur significant loss for speculators and demonstrate a "reversal-recovery-underperformance" pattern. Empirical analysis confirms these predictions. China’s 2020 GEM reform, which widened the price limit from 10% to 20%, provides further causal evidence that relaxed limits mitigate speculative distortions.
北京大学经济学院
国际商务硕士讲座
结合海外需求的企业对外经贸合作——以中国企业对韩国投资为例
主讲人：俞海燕（中国贸促会（CCPIT）驻韩国代表处前总代表、韩国中国商会前执行会长）
主持人：陈仪（北京大学经济学院国际经济与贸易系主任、副教授）
时间：2025年9月26日（周五）10:00-11:30
地点：北京大学经济学院305会议室
主讲人简介：
俞海燕博士曾任中国国际贸易促进委员会（CCPIT）驻韩国代表处总代表、韩国中国商会执行会长。俞博士常年耕耘于我国对外经贸合作领域，尤其熟知中韩经贸政策和实务，以及中国企业对韩国投资经营实践，为服务中资企业、推动中韩交流与合作做出了重要贡献。
供稿：科研与博士后办公室
美编：闻听
责编：度量、雨禾、雨田
