Margherita Comola

We study the role of social learning in the diffusion of cash crops in a resettled village economy in Brazil. We combine detailed geo-coded data on farming plots with dyadic data on social ties among settlers, and we leverage the variation in network formation induced by the landless workers’ movement land occupation. By using longitudinal data on farming decisions over 15 years, we find evidence of significant peer effects in the decision to farm new cash fruits (pineapple and passion fruit). Our results suggest that social diffusion is heterogeneous along observed plot and crop characteristics, i.e. farmers growing water-sensitive crop are more likely to respond to the actions of peers with similar water access conditions.

This paper studies how formal financial access affects network-based financial arrangements. We use a field experiment that granted access to a savings account to a random subset of households in 19 Nepalese villages. Exploiting a unique panel dataset that follows all bilateral informal financial transactions before and after the intervention, we show that households that were offered access to an account increased their loans and total transfers to others, independent of the treatment status of the receiver. The increase seemed to be driven by treatment households with more assets and greater financial inclusion at baseline.

Networks may rewire in response to interventions. We propose a measure of the treatment effect when an intervention affects the structure of a social network. We develop a treatment-response model that incorporates dynamic peer effects and provide its identification conditions and the associated instrumental-variable strategy. We illustrate our estimation procedure using a panel dataset containing information on a financial network before and after a field experiment that randomized access to savings accounts. Results show that neglecting the network change results in underestimation of the impact of the intervention and the role played by informal networks through which the intervention diffuses.

La vie quotidienne est le cadre d’interactions personnelles et professionnelles qui constituent l’un des moteurs du comportement et du succès de chacun. M. Comola nous propose de parcourir des situations diverses – recherche d’emploi, transmission d’informations, usage des plateformes numériques, recours aux technologies, mécanismes d’assurance, commerce ou encore discrimination sociale – dans lesquelles ce sont les liens sociaux qui font la différence entre la réussite et l’échec. On constate alors que ces liens, loin de se limiter à la sphère privée, acquièrent une dimension économique qu’il convient de mettre au coeur du débat public.