FSS-DECO Seminar: Confidential Implementation – Ask (Tell) Only What is Necessary
Speaker: Prof. Soo Hong CHEW, Director and Chief Professor, Department of Economics Center for Intelligence Economic Science, Southwestern University of Finance and Economics, China
Date: 9 April 2026 (Thursday)
Time: 14:00-15:15
Venue: E21B-G002
Language: English
Abstract: Collective decision making to attain social objectives relies on aggregating individuals’ private information. Motivated by increasingly pervasive privacy concerns, we study confidentiality of the implementation of a collective decision making rule beyond the well-discussed notion of anonymity. We introduce two privacy criteria. Intrusiveness refers to privacy loss arising from the administrator’s undue collection of private information beyond what is necessary for determining social outcomes. Building on intrusiveness, exposedness concerns another form of privacy loss: undue disclosure of certain agents’ private information to other agents unnecessary for conditional information revelation. An implementation is confidential if it is least intrusive and least exposing. We characterize confidential implementation using a class of dynamic mechanisms, called gradual mechanism, that makes the flow of information explicit and provides an analogue of the revelation principle. We offer two transformations on gradual mechanisms to enhance confidentiality. One reduces intrusiveness by merging duplicate actions. The other reduces exposedness by obfuscating superfluous information. An implementation is confidential if and only if no derived gradual mechanism admits either transformation. Applications include auction, matching, and voting.
