讲座题目：Belief hedges: applying ambiguity measurements to all events and all ambiguity models

　　报告人：李晨

　　报告时间：2019年2月22日下午3:30-5:00

　　报告地点：经管院A208

　　主办单位：数理经济与数理金融系

　　主持人：魏立佳

　　摘要:When measuring ambiguity attitudes one should control for subjective beliefs, but those are usually not directly observable. Hence, measurements focused on artificial events (secretized urns or researcher-specified probability intervals), where beliefs could be inferred from symmetry conditions. Such symmetries are rarely available for application-relevant events. This paper shows that ambiguity attitudes still can be identified by using belief hedges, i.e., collections of events that protect against unknown beliefs the same way as financial hedges protect against unknown payoffs. Using belief hedges, we can define model-free indexes of ambiguity attitudes, which can be used under all popular ambiguity models today. We also ensure that the indexes are directly observable from revealed preferences. The indexes agree with existing indexes where ever those are defined, showing that they properly capture the underlying ambiguity concepts. We axiomatize our indexes and discuss their limitations.

　　简介：Dr. Chen Li is an assistant professor in behavioral economics at Erasmus University Rotterdam (the Netherlands). Her research focuses on ambiguity attitudes, including their measurement, relations to people’s well-being, and how to help people better handle uncertainties. She has published on prestigious journals including Management Science, Experimental Economics, Journal or Risk and Uncertainty, Journal of Mathematical Psychology, and Theory and Decision.