Friend-Based Ranking

49 Pages Posted: 4 Aug 2018 Last revised: 27 Oct 2019

See all articles by Francis Bloch

Francis Bloch

Paris School of Economics (PSE)

Matthew Olckers

Monash University - Department of Economics

Date Written: October 24, 2019


We analyze the design of a mechanism to extract a ranking of individuals according to a unidimensional characteristic, such as ability or need. Individuals, connected on a social network, only have local information about the ranking. We show that a planner can construct an ex post incentive compatible and efficient mechanism if and only if every pair of friends has a friend in common. We characterize the windmill network as the sparsest social network for which the planner can always construct a complete ranking.

Keywords: social networks, mechanism design, peer ranking, targeting

JEL Classification: D85, D82, O12, D71

Suggested Citation

Bloch, Francis and Olckers, Matthew, Friend-Based Ranking (October 24, 2019). Available at SSRN: or

Francis Bloch

Paris School of Economics (PSE) ( email )

48 Boulevard Jourdan
Paris, 75014 75014

Matthew Olckers (Contact Author)

Monash University - Department of Economics ( email )

Wellington Road
Clayton, Victoria 3

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