Yann Bramoullé

Chercheur ,  CNRS

Développement et économie politique
Bramoullé
Statut
Directeur de recherche
Domaine(s) de recherche
Économie de l'environnement, Théorie des jeux et réseaux sociaux
Thèse
2002, University of Maryland
Téléchargement
CV
Contact
yann.bramoulle[at]univ-amu.fr
+33(0)4 13 55 25 34 / +33(0)4 13 94 20 06
Adresse

AMU - AMSE
5-9 Boulevard Maurice Bourdet, CS 50498
​13205 Marseille Cedex 1

Site
http://sites.google.com/site/bramoulley/
Résumé This paper studies the dynamics of information diffusion within networks, encompassing both general and targeted dissemination. We first characterize the theoretical foundations of diffusion centrality. Next, we introduce two extensions of diffusion centrality: targeting centrality and reachability, that we believe to better capture situations involving targeted requests. We derive general explicit formulas for the computation of these novel centrality measures.
Mots clés Diffusion, Centrality, Political intermediation, Targeting
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Résumé What patterns of economic relations arise when people are altruistic rather than strategically self-interested? What are the welfare implications of altruistically-motivated choices of business partners? This paper introduces an altruism network into a simple model of choice among partners for economic activity. With concave utility, agents effectively become inequality averse towards their friends and family. Rich agents preferentially choose to work with poor friends despite productivity losses. These preferential contracts can also align with welfare since the poor benefit the most from income gains and these gains can outweigh the loss in output. Hence, network inequality—the divergence in incomes within sets of friends and family—is key to how altruism shapes economic activity, output, and welfare. When skill homophily —the tendency for friends to have the skills needed for high production—is high, preferential contracts and productivity losses disappear since rich agents have poor friends with the requisite qualifications.
Mots clés Networks, Altruism, Income inequality, Connections
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Résumé We study how altruism networks affect the demand for formal insurance. Agents with CARA utilities are connected through a network of altruistic relationships. Incomes are subject to a common shock and to a large individual shock, generating heterogeneous damages. Agents can buy formal insurance to cover the common shock, up to a coverage cap. We find that ex-post altruistic transfers induce interdependence in ex-ante formal insurance decisions. We characterize the Nash equilibria of the insurance game and show that agents act as if they are trying to maximize the expected utility of a representative agent with average damages. Altruism thus tends to increase demand of low-damage agents and to decrease demand of high-damage agents. Its aggregate impact depends on the interplay between demand homogenization, the zero lower bound and the coverage cap. We find that aggregate demand is higher with altruism than without altruism at low prices and lower at high prices. Nash equilibria are constrained Pareto efficient.
Mots clés Altruism networks, Informal transfers, Formal insurance
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Résumé Historically and in many parts of the developing world, ethnic minorities have played a central role in the economy. Examples include Chinese throughout South-east Asia, Indians in East Africa, and Jews in medieval Europe. These rich minorities are often subject to popular violence and extortion, and are treated ambiguously by local politicians. We analyse the impact of the presence of a rich ethnic minority on violence and on interactions between a rent-seeking local elite and a poor majority. We find that the local elite can always make use of the rich minority to maintain its hold on power. When the threat of violence is high, the government may change its economic policies strategically to sacrifice the minority to popular resentment. We investigate the conditions under which such instrumental scapegoating emerges, and the forms it takes. We then introduce some social integration, capturing, for instance, mixed marriages and shared education. Social integration reduces violence and yields qualitative changes in economic policies. Overall, our results help to explain documented patterns of violence and segregation.
Mots clés Scapegoat, Ethnic minority, Popular violence, Elites
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Résumé We provide the first analysis of the risk-sharing implications of altruism networks. Agents are embedded in a fixed network and care about each other. We explore whether altruistic transfers help smooth consumption and how this depends on the shape of the network. We find that altruism networks have a first-order impact on risk. Altruistic transfers generate efficient insurance when the network of perfect altruistic ties is strongly connected. We uncover two specific empirical implications of altruism networks. First, bridges can generate good overall risk sharing, and, more generally, the quality of informal insurance depends on the average path length of the network. Second, large shocks are well-insured by connected altruism networks. By contrast, large shocks tend to be badly insured in models of informal insurance with frictions. We characterize what happens for shocks that leave the structure of giving relationships unchanged. We further explore the relationship between consumption variance and centrality, correlation in consumption streams across agents, and the impact of adding links.
Mots clés Informal Insurance, Risk sharing, Networks, Altruism
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Résumé We survey the recent, fast-growing literature on peer effects in networks. An important recurring theme is that the causal identification of peer effects depends on the structure of the network itself. In the absence of correlated effects, the reflection problem is generally solved by network interactions even in nonlinear, heterogeneous models. By contrast, microfoundations are generally not identified. We discuss and assess the various approaches developed by economists to account for correlated effects and network endogeneity in particular. We classify these approaches in four broad categories: random peers, random shocks, structural endogeneity, and panel data. We review an emerging literature relaxing the assumption that the network is perfectly known. Throughout, we provide a critical reading of the existing literature and identify important gaps and directions for future research.
Mots clés Measurement errors, Randomization, Causal effects, Identification, Peer effects, Social networks
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Résumé Many regulations with first-order economic and environmental consequences have to be adopted under significant scientific uncertainty. Examples include tobacco regulations in the second half of the 20th century, climate change regulations and current regulations on pesticides and neonicotinoid insecticides. Firms and industries have proved adept at exploiting such scientific uncertainty to shape and delay regulation. The main strategies documented include: hiring and funding dissenting scientists, producing and publicizing favorable scientific findings, ghostwriting, funding diversion research, conducting large-scale science-denying communication campaigns, and placing experts on advisory and regulatory panels while generally concealing involvement. In many cases, special interests have thus deliberately manufactured doubt and these dishonest tactics have had large welfare consequences. Largely and unduly neglected by economists, these doubt-manufacturing strategies should now be addressed by the field. Here, we first present a simple theoretical framework providing a useful starting point for considering these issues. The government is benevolent but populist and maximizes social welfare as perceived by citizens. The industry can produce costly reports showing that its activity is not harmful, and citizens are unaware of the industry’s miscommunication. This framework raises important new questions, such as how industry miscommunication and citizens’ beliefs are related to scientific uncertainty. It also sheds new light on old questions, such as the choice of policy instrument to regulate pollution. We subsequently outline a tentative roadmap for future research, highlighting critical issues in need of more investigation.
Mots clés Lobbying, Scientific Uncertainty, Biased Research, Populist Policies, Incertitude scientifique, Lobbying, Politique populiste, Recherche biaisée
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Résumé In their efforts to affect regulations, firms have developed specific strategies to exploit scientific uncertainty. They have manufactured doubt by hiring and funding dissenting scientists, by producing and publicizing favorable scientific findings and by generally concealing their involvement in biased research. We propose a new model to study the interplay between scientific uncertainty, firms' miscommunication and public policies. The government is benevolent but populist, and maximizes social welfare as perceived by citizens. The industry can produce costly reports showing that its activity is not harmful. Citizens are unaware of the industry's miscommunication. We first characterize the industry's optimal miscommunication policy. The industry notably ceases miscommunicating abruptly when scientists' belief reaches a critical threshold. We identify a natural condition under which miscommunication is stronger under a tax on emissions than under command and control. We then analyze research funding. A populist government may support research to enable firms to falsely reassure citizens. Establishing an independent research agency helps limit the welfare losses induced by populist policies.
Mots clés Populist Policies, Environmental Policy Instruments, Scientific Uncertainty, Research Funding
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Résumé We document strong and robust negative correlations between the length of the title of an economics article and different measures of scientific quality. Analyzing all articles published between 1970 and 2011 and referenced in EconLit, we find that articles with shorter titles tend to be published in better journals, to be more cited and to be more innovative. These correlations hold controlling for unobserved time-invariant and observed time varying characteristics of teams of authors. (C) 2018 Elsevier B.V. All rights reserved.
Mots clés Novelty, Citations, Journal quality, Title length
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Résumé We provide the first analysis of altruism in networks. Agents are embedded in a fixed network and care about the well-being of their network neighbors. Depending on incomes, they may provide financial support to their poorer friends. We study the Nash equilibria of the resulting game of transfers. We show that equilibria maximize a concave potential function. We establish existence, uniqueness of equilibrium consumption, and generic uniqueness of equilibrium transfers.We characterize the geometry of the network of transfers and highlight the key role played by transfer intermediaries. We then study comparative statics. A positive income shock to an individual benefits all. For small changes in incomes, agents in a component of the network of transfers act as if they were organized in an income-pooling community. A decrease in income inequality or expansion of the altruism network may increase consumption inequality.
Mots clés Inequality, Neutrality, Social networks, Altruism, Private transfers, Economie quantitative
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Résumé Favoritism refers to the act of offering jobs, contracts and resources to members of one's own social group in preference to others who are outside the group. This paper examines the economic origins and the consequences of favoritism.
Mots clés Favoritism, Inequalities, Rents, Surplus diversion
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Résumé The Oxford Handbook of the Economics of Networks represents the frontier of research into how and why networks they form, how they influence behavior, how they help govern outcomes in an interactive world, and how they shape collective decision making, opinion formation, and diffusion dynamics. From a methodological perspective, the contributors to this volume devote attention to theory, field experiments, laboratory experiments, and econometrics. Theoretical work in network formation, games played on networks, repeated games, and the interaction between linking and behavior is synthesized. A number of chapters are devoted to studying social process mediated by networks. Topics here include opinion formation, diffusion of information and disease, and learning. There are also chapters devoted to financial contagion and systemic risk, motivated in part by the recent financial crises. Another section discusses communities, with applications including social trust, favor exchange, and social collateral; the importance of communities for migration patterns; and the role that networks and communities play in the labor market. A prominent role of networks, from an economic perspective, is that they mediate trade. Several chapters cover bilateral trade in networks, strategic intermediation, and the role of networks in international trade. Contributions discuss as well the role of networks for organizations. On the one hand, one chapter discusses the role of networks for the performance of organizations, while two other chapters discuss managing networks of consumers and pricing in the presence of network-based spillovers. Finally, the authors discuss the internet as a network with attention to the issue of net neutrality. Contributors to this volume - Daron Acemoglu Sinan Aral Lori Beaman Francis Bloch Vincent Boucher Yann Bramoulle Emily Breza Antonio Cabrales Arun Chandrasekhar Thomas Chaney Syngjoo Choi Daniele Condorelli Wouter Dessein Marcin Dziubinski Nick Economides
Mots clés Economie quantitative
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Résumé no abstract
Mots clés Economie quantitative
HAL Google Scholar
Résumé The Oxford Handbook of the Economics of Networks represents the frontier of research into how and why networks they form, how they influence behavior, how they help govern outcomes in an interactive world, and how they shape collective decision making, opinion formation, and diffusion dynamics. From a methodological perspective, the contributors to this volume devote attention to theory, field experiments, laboratory experiments, and econometrics. Theoretical work in network formation, games played on networks, repeated games, and the interaction between linking and behavior is synthesized. A number of chapters are devoted to studying social process mediated by networks. Topics here include opinion formation, diffusion of information and disease, and learning. There are also chapters devoted to financial contagion and systemic risk, motivated in part by the recent financial crises. Another section discusses communities, with applications including social trust, favor exchange, and social collateral; the importance of communities for migration patterns; and the role that networks and communities play in the labor market. A prominent role of networks, from an economic perspective, is that they mediate trade. Several chapters cover bilateral trade in networks, strategic intermediation, and the role of networks in international trade. Contributions discuss as well the role of networks for organizations. On the one hand, one chapter discusses the role of networks for the performance of organizations, while two other chapters discuss managing networks of consumers and pricing in the presence of network-based spillovers. Finally, the authors discuss the internet as a network with attention to the issue of net neutrality. Contributors to this volume - Daron Acemoglu Sinan Aral Lori Beaman Francis Bloch Vincent Boucher Yann Bramoulle Emily Breza Antonio Cabrales Arun Chandrasekhar Thomas Chaney Syngjoo Choi Daniele Condorelli Wouter Dessein Marcin Dziubinski Nick Economides
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Résumé Geography and social links shape economic interactions. In industries, schools, and markets, the entire network determines outcomes. This paper analyzes a large class of games and obtains a striking result. Equilibria depend on a single network measure: the lowest eigenvalue. This paper is the first to uncover the importance of the lowest eigenvalue to economic and social outcomes. It captures how much the network amplifies agents' actions. The paper combines new tools--potential games, optimization, and spectral graph theory--to solve for all Nash and stable equilibria and applies the results to R&D, crime, and the econometrics of peer effects.
Mots clés Geography economic, Social economic, Industry, School, Market, Game
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Résumé We provide the first empirical application of a new approach proposed by Lee (Journal of Econometrics 2007; 140(2), 333–374) to estimate peer effects in a linear-in-means model when individuals interact in groups. Assumingsufficient group size variation, this approach allows to control for correlated effects at the group level and to solve the simultaneity (reflection) problem. We clarify the intuition behind identification of peer effects in the model. We investigate peer effects in student achievement in French, Science, Mathematics and History in secondary schools in the Province of Québec (Canada). We estimate the model using conditional maximum likelihood and instrumental variables methods. We find some evidence of peer effects. The endogenous peer effect is large and significant in Mathematics but imprecisely estimated in the other subjects. Some contextual peer effects are also significant. In particular, for most subjects, the average age of peers has a negative effect on own test score. Using calibrated Monte Carlo simulations, we find that high dispersion in group sizes helps with potential issues of weak identification. Copyright © 2012 John Wiley & Sons, Ltd.
Mots clés Economie quantitative
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Résumé We study network games under strategic complementarities. Agents are embedded in a fixed network. They choose a positive, continuous action and interact with their network neighbors. Interactions are positive and actions are bounded from above. We first derive new sufficient conditions for uniqueness, covering all concave as well as some non-concave best responses. We then study the relationship between position and action and identify situations where a more central agent always plays a higher action in equilibrium. We finally analyze comparative statics. We show that a shock may not propagate throughout the entire network and uncover a general pattern of decreasing interdependence.
Mots clés Uniqueness, Strategic complementarities, Network games, Interdependence, Centrality
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Résumé No abstract is available for this item.
Mots clés Economie quantitative
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Résumé Between 1954 and 1998, the tobacco industry funded more than 1,900 research projects at a total cost of $355 million, on topics such as the roles of heredity and nutrition in cancer. Even though legitimate, this research was intended to divert attention from the harmful effects of tobacco. We provide the first formal analysis of such diversion research. We show that special interests may have strong incentives to affect the scientific agenda, even when the research itself is unbiased. This form of scientific lobbying yields large welfare losses and raises concerns about the private funding of research.
Mots clés Scientific Uncertainty, Scientific lobbying, Private research funding
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Résumé In this paper, we use tools from network theory to trace the properties of the matching function to the structure of granular connections between applicants and firms. We link seemingly disparate parts of the literature and recover existing functional forms as special cases. Our overarching message is that structure counts. For rich structures, captured by non-random networks, the matching function depends on whole sets rather than just the sizes of the two sides of the market. For less rich-random network-structures it depends on the sizes of the two sides and a few structural parameters. Structures characterized by greater asymmetries reduce the matching function's efficacy, while denser structures can have ambiguous effects on it. For the special case of the Erdös-Rényi network, we show that the way the network varies with the sizes of the two sides of the market determines if the matching function exhibits constant returns to scale, or even if it is of a specific functional form, such as CES.
Mots clés Bocconi University, IGIER, Bramoullé
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Résumé We introduce loss aversion into a model of conspicuous consumption in networks. Agents allocate their income between a standard good and a status good to maximize a Cobb-Douglas utility. Agents interact over a connected network and compare their status consumption to their neighbors' average consumption. Loss aversion has a profound impact. If loss aversion is large enough relative to income heterogeneity, a continuum of Nash equilibria appears and all agents consume the same quantity of status good. Otherwise, there is a unique Nash equilibrium and richest agents earn strict status gains while poorest agents earn strict status losses.
Mots clés Loss aversion, Conspicuous Consumption, Social networks
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Résumé What patterns of economic relations arise when people are altruistic rather than strategically self-interested? This paper introduces an altruism network into a simple model of choice among partners for economic activity. With concave utility, agents effectively become inequality averse towards friends and family. Rich agents preferentially choose to work with poor friends despite productivity losses. Hence, network inequality-the divergence in incomes within sets of friends and family-is key to how altruism shapes economic relations and output. Skill homophily also plays a role; preferential contracts and productivity losses decline when rich agents have poor friends with requisite skills.
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Résumé We study a two-period one-to-one dynamic matching environment in which agents meet randomly and decide whether to match early or defer. Crucially, agents can match with either partner in the second period. This "recall" captures situations where, e.g., a firm and worker can conduct additional interviews before contracting. Recall has a profound impact on incentives and on aggregate outcomes. We show that the likelihood to match early is nonmonotonic in type: early matches occur between the good-but-not-best agents. The option value provided by the first-period partner provides a force against unraveling, so that deferrals occur under small participation costs.
Mots clés Dynamic matching, Unraveling, Recall
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Résumé We study how altruism networks affect the adoption of formal insurance. Agents have private CARA utilities and are embedded in a network of altruistic relationships. Incomes are subject to both a common shock and a large idiosyncratic shock. Agents can adopt formal insurance to cover the common shock. We show that ex-post altruistic transfers induce interdependence in ex-ante adoption decisions. We characterize the Nash equilibria of the insurance adoption game. We show that adoption decisions are substitutes and that the number of adopters is unique in equilibrium. The demand for formal insurance is lower with altruism than without at low prices, but higher at high prices. Remarkably, individual incentives are aligned with social welfare. We extend our analysis to CRRA utilities and to a fixed utility cost of adoption.
Mots clés Formal insurance, Informal transfers, Altruism networks
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Résumé Heckman and MaCurdy (1985) first showed that binary outcomes are compatible with linear econometric models of interactions. This key insight was unduly discarded by the literature on the econometrics of games. We consider general models of linear interactions in binary outcomes that nest linear models of peer effects in networks and linear models of entry games. We characterize when these models are well defined. Errors must have a specific discrete structure. We then analyze the models' game-theoretic microfoundations. Under complete information and linear utilities, we characterize the preference shocks under which the linear model of interactions forms a Nash equilibrium of the game. Under incomplete information and independence, we show that the linear model of interactions forms a Bayes-Nash equilibrium if and only if preference shocks are iid and uniformly distributed. We also obtain conditions for uniqueness. Finally, we propose two simple consistent estimators. We revisit the empirical analyses of teenage smoking and peer effects of Lee, Li, and Lin (2014) and of entry into airline markets of Ciliberto and Tamer (2009). Our reanalyses showcase the main interests of the linear framework and suggest that the estimations in these two studies suffer from endogeneity problems.
Mots clés Binary Outcomes, Linear Probability Model, Peer effects, Econometrics of Games
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Résumé We survey the recent, fast-growing literature on peer effects in networks. An important recurring theme is that the causal identification of peer effects depends on the structure of the network itself. In the absence of correlated effects, the reflection problem is generally solved by network interactions even in non-linear, heterogeneous models. By contrast, microfounda-tions are generally not identified. We discuss and assess the various approaches developed by economists to account for correlated effects and network endogeneity in particular. We classify these approaches in four broad categories: random peers, random shocks, structural endogeneity and panel data. We review an emerging literature relaxing the assumption that the network is perfectly known. Throughout, we provide a critical reading of the existing literature and identify important gaps and directions for future research.
Mots clés Randomization, Measurement errors, Causal effects, Identification, Peer effects, Social networks
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Résumé We provide the first analysis of the risk-sharing implications of altruism networks. Agents are embedded in a fixed network and care about each other. We study whether altruistic transfers help smooth consumption and how this depends on the shape of the network. We identify two benchmarks where altruism networks generate efficient insurance: for any shock when the network of perfect altruism is strongly connected and for any small shock when the network of transfers is weakly connected. We show that the extent of informal insurance depends on the average path length of the altruism network and that small shocks are partially insured by endogenous risk-sharing communities. We uncover complex structural effects. Under iid incomes, central agents tend to be better insured, the consumption correlation between two agents is positive and tends to decrease with network distance, and a new link can decrease or increase the consumption variance of indirect neighbors. Overall, we show that altruism in networks has a first-order impact on risk and generates specific patterns of consumption smoothing.
Mots clés Altruism, Networks, Risk sharing, Informal Insurance
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Résumé We first clarify the precise theoretical foundations behind the notion of diffusion centrality. This allows us to address a minor inconsistency in the model description of Banerjee et al. (2013). We then identify unnatural implicit assumptions in the model of political intermediation proposed by Cruz, Labonne & Querubfn (2017). We introduce two extensions of diffusion centrality, targeting centrality and reachability, which we believe better capture features of contexts with targeted requests. We derive general explicit formulas to compute these new measures.
Mots clés Diffusion centrality, Katz-Bonacich centrality, Political intermediation, Targeting
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Résumé In many parts of the developing world, ethnic minorities play a central role in the economy. Examples include Chinese throughout Southeast Asia, Indians in East Africa and Lebanese in West Africa. These rich minorities are often subject to popular violence and extortion, and are treated ambiguously by local politicians. We analyze the impact of the presence of a rich ethnic minority on violence and on interactions between a rent-seeking local elite and a poor majority. We find that the local elite can always make use of the rich minority to maintain its hold on power. When the threat of violence is high, the government may change its economic policies strategically to sacrifice the minority to popular resentment. We investigate the conditions under which such instrumental scapegoating emerges, and the forms it takes. We then consider some social integration capturing, for instance, mixed marriages and shared education. Social integration reduces violence and yields qualitative changes in economic policies. Overall, our results help explain documented patterns of violence and segregation.
Mots clés Elites, Popular violence, Ethnic minority, Scapegoat
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Résumé Connections appear to be helpful in many contexts such as obtaining a job, a promotion, a grant, a loan or publishing a paper. This may be due to favoritism or to information conveyed by connections. Attempts at identifying both effects have relied on measures of true quality, generally built from data collected long after promotion. This empirical strategy faces important limitations. Building on earlier work on discrimination, we propose a new method to identify favors and information from classical data collected at time of promotion. Under natural assumptions, we show that promotion decisions look more random for connected candidates, due to the information channel. We obtain new identification results and show how probit models with heteroscedasticity can be used to estimate the strength of the two effects. We apply our method to the data on academic promotions in Spain studied in Zinovyeva & Bagues (2015). We find evidence of both favors and information effects at work. Empirical results are consistent with evidence obtained from quality measures collected five years after promotion.
Mots clés Promotion, Connections, Social networks, Favoritism, Information
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Résumé In their persistent fight to affect regulation, firms have developed specific strategies to exploit scientific uncertainty. They have spent large amounts of money to generate and publicize favorable scientific findings, to discredit and downplay unfavorable ones and to shape the public’s perceptions through large-scale communication campaigns. We develop a new model to study the interplay between scientific uncertainty, firms’ communication and public policies. The government is benevolent but populist and maximizes social welfare as perceived by citizens. The industry can provide costly evidence that its activity is not harmful. Citizens incorrectly treat the industry’s information on par with scientific knowledge. We characterize the industry’s optimal communication policy. As scientists become increasingly convinced that the industrial activity is harmful, firms first devote more and more resources to reassure people. When scientists’ beliefs reach a critical threshold, however, the industry stops its efforts abruptly. We then study the impact of firms’ communication on scientific funding. A populist government may, perversely, want to support research to better allow firms to miscommunicate. Populist policies can entail significant welfare losses. Establishing an independent funding agency always reduces these losses and may lead to under- or over- investment in research with respect to the first-best.
Mots clés Scientific Uncertainty, Populist Policies, Indirect lobbying, Research Funding
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Résumé This chapter studies games played on fixed networks. These games capture a wide variety of economic settings including local public goods, peer effects, and technology adoption. We establish a common analytical framework to study a wide game class. We unearth new connections between games in the literature and in particular between those with binary actions, like coordination and best-shot games, and those with continuous actions and linear best replies. We review and advance existing results by showing how they tie together within the common framework. We discuss the game-theoretic underpinnings of key notions including Bonacich centrality, maximal independent sets, and the lowest and largest eigenvalue. We study the interplay of individual heterogeneity and the network and we develop a new notion - interdependence - to analyze how a shock to one agent affects the action of another agent. We outline directions for future research.
Mots clés Network games, Fixed networks, Peer effects, Coordination, Interdependence
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Résumé We provide the first theoretical analysis of altruism in networks. Agents are embedded in a fixed, weighted network and care about their direct friends. Given some initial distribution of incomes, they may decide to support their poorer friends. We study the resulting non-cooperative transfer game. Our analysis highlights the importance of indirect gifts, where an agent gives to a friend because his friend himself has a friend in need. We uncover four main features of this interdependence. First, we show that there is a unique profile of incomes after transfers, for any network and any utility functions. Uniqueness in transfers holds on trees, but not on arbitrary networks. Second, there is no waste in transfers in equilibrium. In particular, transfers flow through indirect paths of highest altruistic strength. Third, a negative shock on one agent cannot benefit others and tends to affect socially closer agents first. In addition, an income redistribution that decreases inequality ex-ante can increase inequality ex-post. Fourth, altruistic networks decrease income inequality. In contrast, more altruistic or more homophilous networks can increase inequality.
Mots clés Social networks, Private transfers, Altruism, Income Redistribution, Income inequality
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Résumé We study network games with linear best-replies and strategic complementarities. We assume that actions are continuous but bounded from above. We show that there is always a unique equilibrium. We find that two key features of these games under small network effects may not hold when network effects are large. Action may not be aligned with network centrality and the interdependence between agents' actions may be broken.
Mots clés Network games, Strategic complementarities, Supermodular Games, Bonacich centrality
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