Accepted and Published Papers
M. Lambotte, "Peer effects in binary outcomes: strategic complementarity and taste for conformity with endogenous network", Journal of Applied Econometrics, 2025. Replication
M. Lambotte, S. Mathy, A. Risch and C. Treibich, “Disentangling peer effects in transportation mode choice: the example of active commuting", Journal of Environmental Economics and Management, 2023. Media coverage: The Conversation
M. Lambotte, S. De Cara, C. Brocas, and V. Bellassen, “Organic farming offers promising mitigation potential in dairy systems without compromising economic performances”, Journal of Environmental Management, 2023.
M. Lambotte, S. De Cara, C. Brocas, and V. Bellassen, “Carbon footprint and economic performance of dairy farms: The case of Protected Designation of Origin farms in France”, Agricultural Systems, 2021.
M. Lambotte, S. De Cara, and V. Bellassen, “Once a quality food consumer, always a quality food consumer? Consumption patterns of organic, label rouge and geographical indications in French scanner data”, Review of Agricultural, Food and Environmental Studies, 2020.
Working papers :
Asymmetries in Peer Effects — with A. Houndetoungan. arXiv (August 2026) — Replication — R Package
Individuals are often influenced by their peers because deviating from prevailing behavior entails social costs. However, existing peer effects models typically assume that individuals respond similarly to peers who perform better or worse than they do. This paper introduces a novel structural model of asymmetric peer effects in which conformity incentives depend on whether individuals perform below or above each of their peers. We establish that the model admits a unique equilibrium and show that its parameters can be identified and estimated through simple moment conditions. Applying our method to several student outcomes, we uncover strong evidence of asymmetries in peer effects. We then demonstrate that these asymmetries are highly policy-relevant by studying targeted interventions under budget constraints. Ignoring asymmetries leads to inefficient treatment allocation and substantial welfare losses, reducing welfare to levels comparable to those in a benchmark without social interactions.
Conformity, Competition, and Voluntary Price Regulation: Evidence from French Physicians — with B. Montmartin. Draft (November 2025) — R&R at the Journal of the European Economic Association
This paper proposes a structural framework to analyze firms’ voluntary participation in a price-freeze scheme under monopolistic competition. We develop a binary choice model under incomplete information that captures two distinct micro-founded interaction mechanisms: spatial competition and conformity to social norms, which are particularly relevant for the self-employed. We apply our game-theoretic framework to analyze the adoption of a novel pricing scheme offered to French balance-billing physicians, designed to freeze fees while compensating them through economic benefits. Our analysis leverages a unique geolocalized dataset covering the entire population of pediatricians, gynecologists, and ophthalmologists. We find compelling evidence of a significant preference for conformity, whereas competitive interactions appear to play a negligible role in physicians’ decision-making. These findings offer a strong rationale for the observed low adoption rate of this pricing regulation policy.
Heterogeneity in peer effects for binary outcomes — arXiv (May 2026), Under Review.
I introduce heterogeneity into the analysis of peer effects arising from conformity by allowing peer-effect parameters to vary across agents’ actions. Using a structural model based on a simultaneous network game with incomplete information, I derive conditions that guarantee the uniqueness of the equilibrium and the identification of heterogeneous peer-effect parameters. Applying the model to data on smoking and alcohol consumption among secondary school students, and conducting policy simulations, I show that assuming a homogeneous preference for conformity leads to biased estimates of peer effects and ex ante policy evaluations
Work in progress
Intergenerational Transmission of Smoking Behavior — with J. Thuilliez and N. Touré
Peer, Parents and ADHD: Network Formation, Parental Investments and Educational Outcomes — with M. Tholimet
Access to Care and Avoidable Consultations: The Redistributive Effects of e-Consultations — with S. Karimi
Demand systems with endogenous variety regime and corner solutions (A draft of the model and estimation strategy is available upon request)
Modeling and estimating demand systems with differentiated products at a disaggregated scale is a challenging task due to the high number of corner solutions. I propose a discrete-continuous model that accounts for the endogenous formation of the consideration set. Consumers first choose their variety regime while being subject to cognitive and time costs. Then, they select the optimal non-negative (continuous) quantities of each variety-product pair. The model we propose is highly flexible as it accommodates the fact that consumers might never purchase some products, varieties or some variety-product pairs. This demand system is estimated on highly censored data from conventional and organic purchases, using the 2019 French Kantar WorldPanel.