Testing Mechanisms（测试机制）
主讲人：Soonwoo Kwon（Brown University）
主持老师：（北大国发院）孙振庭
参与老师：（北大经院）王一鸣、王熙、刘蕴霆、王法
（北大国发院）黄卓、张俊妮
（北大新结构）胡博
时间：2023年11月3日（周五） 10:00-11:30
地点（线上）：Zoom 会议
https://us06web.zoom.us/j/82552841093?pwd=UJbsL2dsKlsSp9syr3tXVUXlfpf82I.1
会议号: 825 5284 1093，密码: 069107
报告摘要：
Economists are often interested in the mechanisms by which a particular treatment affects an outcome. This paper develops tests for the “sharp null of full mediation” that the treatment D operates on the outcome Y only through a particular conjectured mechanism (or sets of mechanisms) M. A key observation is that if D is randomly assigned and has a monotone effect on M, then D is a valid instrumental variable for the LATE of M on Y. Existing tools for testing the validity of the LATE assumptions can thus be used to test the sharp null of full mediation when M and D are binary. We extend these results to settings where M is multi-valued or multi-dimensional. We further provide methods for lower-bounding the size of the alternative mechanisms when the sharp null is rejected. An advantage of our approach relative to existing tools for mediation analysis is that it does not require stringent assumptions about how M is assigned.
主讲人简介：
Soonwoo Kwon is an Assistant Professor of Economics at Brown University. His research interests are in econometric theory and applied econometrics, particularly in robust methods, broadly defined. He has publications at Economic Journal and Quantitative Economics.
