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Who Matters to Whom? Identifying Peer Effects with Propagation Geometry

Guy Tchuente

arXiv 27 Feb 2026 · Econometrics

arXiv:2602.23594 · PDF · DOI · OpenAlex · Extracted main text

Abstract

This paper develops a unifying theory of peer effects that treats the peer aggregator (the social norm mapping peers' actions into a scalar exposure) as the central behavioral primitive. We formulate peer influence as a norm game in which payoffs depend on own action and an exposure index, and we provide equilibrium existence and uniqueness for a broad class of aggregators. Using economically interpretable axioms, we organize commonly used exposure maps into a small taxonomy that nests linear-in-means, CES (peer-preference) norms, and smooth “attention-to-salient-peers” aggregators; rank-based quantile norms are treated as a complementary class. Building on this unification, we show that each aggregator induces an operator that governs how exogenous variation propagates through the network. Linear-in-means corresponds to constant transport (adjacency matrix), recovering the classic (friends-of-friends) instrument families. For nonlinear norms, operator becomes state- and preference-dependent and is characterized by the Jacobian of the exposure map evaluated at an exogenous predictor. This perspective yields geometry-induced instrument that exploit heterogeneity in marginal influence and nonredundant paths, and can remain informative when one-step moments or adjacency-power instruments become weak. Monte Carlo evidence and an application to NetHealth illustrate the practical implications across alternative aggregators and outcomes.

Citation extraction

22
references
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Most heavily cited references

The works this paper leans on most, across its whole bibliography — not restricted to papers in our corpus. Ranked by composite intensity, which combines how often a work is mentioned, how many sections mention it, and how much of that falls in the main text rather than the appendix.

ReferenceIntensityMentionsSectionsMain text
1Boucher, Vincent and Rendall, Michelle and Ushchev, Philip and Zenou… (2024) Toward a general theory of peer effects1.00094100%
2Manski, Charles F (1993) Identification of endogenous social effects: The reflection problem1.00074100%
3Bramoullé, Yann and Djebbari, Habiba and Fortin, Bernard (2009) Identification of peer effects through social networks1.00073100%
4Koenker, Roger and Bassett, Gilbert (1978) Regression Quantiles0.81142100%
5Mat ejka, Filip and McKay, Alisdair (2015) Rational inattention to discrete choices: A new foundation for the multinomial logit model0.81142100%
6McFadden, Daniel (1974) Conditional Logit Analysis of Qualitative Choice Behavior0.81142100%
7Luce, R Duncan and others (1959) Individual choice behavior0.73732100%
8Nesterov, Yu (2005) Smooth minimization of non-smooth functions0.73732100%
9Brock, William A and Durlauf, Steven N (2001) Discrete choice with social interactions0.64422100%
10Arrow, Kenneth J and Chenery, Hollis B and Minhas, Bagicha S and Sol… (1961) Capital-labor substitution and economic efficiency0.51121100%

Showing the top 10 of 22 scored citations.