Template-Type: ReDIF-Paper 1.0 Author-Name: Francis Bloch Author-Name-First: Francis Author-Name-Last: Bloch Author-Email: francis.bloch@univ-paris1.fr Author-Workplace-Name: University Paris and Paris School of Economics Author-Name: Bhaskar Dutta Author-Name-First: Bhaskar Author-Name-Last: Dutta Author-Email: b.dutta@warwick.ac.uk Author-Workplace-Name: University of Warwick and Ashoka University Author-Name: Marcin Dziubinski Author-Name-First: Marcin Author-Name-Last: Dziubinski Author-Email: m.dziubinski@mimuw.edu.pl Author-Workplace-Name: Institute of Informatics, University of Warsaw Title: Selecting a Winner with External Referees Abstract: We consider a problem of mechanism design without money, where a planner selects a winner among a set of agents with binary types and receives outside signals (like the report of external referees). We show that there is a gap between the optimal Dominant Strategy Incentive Compatible (DSIC) mechanism and the optimal Bayesian Incentive Compatible (BIC) mechanism. In the optimal BIC mechanism, the planner can leverage the outside signal to elicit information about agents' types. BIC mechanisms are lexicographic mechanisms, where the planner first shortlists agents who receive high reports from the referees and then uses agents' reports to break ties among agents in the shortlist. We compare the \self-evaluation" mechanism with a "peer evaluation" mechanism where agents evaluate other agents, and show that for the same signal precision, the self- evaluation mechanism outperforms the peer evaluation mechanism. We show that optimal Ex Post Incentive Compatible (EPIC) mechanisms give the planner an intermediate value between the optimal DSIC and BIC mechanisms. length: 107 Creation-Date: 20230420 Revision-Date: Publication-Status: File-URL: https://dp.ashoka.edu.in/ash/wpaper/paper99_0.pdf File-Format: Application/pdf Number: 99 Keywords: Mechanism design without money Keywords: Peer selection Keywords: Bayesian incentive compatibility Keywords: Dominant strategy incentive compatibility Keywords: Ex post incentive compatibility Handle: RePEc:ash:wpaper:99