Public Goods in Endogenous Networks

Date: 2015-10-21
By: Markus Kinateder (​University of Navarra)
Luca Paolo Merlino (Universit e libre de Bruxelles)
In this paper we study a local public good game in an endogenous network with heterogeneous agents. We consider two specifications, in which different networks arise. When agents differ in the cost of acquiring the public good, active agents form hierarchical complete multipartite graphs; yet, better types need not have more neighbors. When agents have heterogeneous benefits from the public good, nested split graphs in which investment need not be monotonic in type emerge. In large societies, few agents are active and the network dampens inequality.
Keywords: public goods,
JEL: C72 D00 D85 H41

Direct and indirect network effects: are they equivalent?

Clements, Matthew T. “Direct and indirect network effects: are they equivalent?." International Journal of Industrial Organization 22.5 (2004): 633-645.


Network effects may be either direct or indirect. While many analyses conflate the two, I show that the ways in which direct and indirect effects influence technological standardization are quite different. Some parameter changes have opposite effects in the two models, and some factors which are irrelevant under direct effects are central under indirect effects. Compatibility in particular has a different interpretation and more subtle implications for standardization in the indirect model.

Network effects, Network externalities, Standards, Compatibility

JEL classification

  • L1

Games Played on Networks

==Notes by yinung==
原本獨立的 game 在 linked network 玩會如何呢?
本文介紹了網路位置 (network position) 觀念, 及其對均衡的影響 (Ballester, CalvÛ-Armengol & Zenou (2006) Örst establish the connection between equilibrium action and Bonacich centrality (Bonacich 1987),另見 Yves Zenou. (2015),   “Key players" (344 Kb) , In: Y. Bramoullé, B.W. Rogers and A. Galeotti (Eds.), Oxford Handbook on the Economics of Networks, Oxford: Oxford University Press, forthcoming. Vox column)
Date: 2015-03
By: Yann Bramoullé (AMSE – Aix-Marseille School of Economics – EHESS – École des hautes études en sciences sociales – Centre national de la recherche scientifique (CNRS) – Ecole Centrale Marseille (ECM) – AMU – Aix-Marseille Université)
Rachel Kranton (Duke University, Department of Economics – Duke University (Durham, USA))
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.

Natural Experiments in Macroeconomics

Date: 2015-05
By: Fuchs-Schündeln, Nicola
Hassan, Tarek
A growing literature relies on natural experiments to establish causal effects in macroeconomics. In diverse applications, natural experiments have been used to verify underlying assumptions of conventional models, quantify specific model parameters, and identify mechanisms that have major effects on macroeconomic quantities but are absent from conventional models. We discuss and compare the use of natural experiments across these different applications and summarize what they have taught us about such diverse subjects as the validity of the Permanent Income Hypothesis, the size of the fiscal multiplier, and about the effects of institutions, social structure, and culture on economic growth. We also outline challenges for future work in each of these fields, give guidance for identifying useful natural experiments, and discuss the strengths and weaknesses of the approach.
Keywords: Civic Capital; Fiscal Multiplier; Institutions; Multiple Equilibria; Networks; Permanent Income Hypothesis; Social Structure; Social Ties; Trust
JEL: C1 C9 E21 E62 H31 O11 O14 O43 O50

Enhanced Gravity Model of trade: reconciling macroeconomic and network models

Date: 2015-06
By: Assaf Almog
Rhys Bird
Diego Garlaschelli
The bilateral trade relations between world countries form a complex network, the International Trade Network (ITN), which is involved in an increasing number of worldwide economic processes, including globalization, integration, industrial production, and the propagation of shocks and instabilities. Characterizing the ITN via a simple yet accurate model is an open problem. The classical Gravity Model of trade successfully reproduces the volume of trade between two connected countries using known macroeconomic properties such as GDP and geographic distance. However, it generates a network with an unrealistically homogeneous topology, thus failing to reproduce the highly heterogeneous structure of the real ITN. On the other hand, network models successfully reproduce the complex topology of the ITN, but provide no information about trade volumes. Therefore macroeconomic and network models of trade suffer from complementary limitations but are still largely incompatible. Here, we make an important step forward in reconciling the two approaches, via the introduction of what we denote as the Enhanced Gravity Model (EGM) of trade. The EGM combines the maximum-entropy nature of network models with the established econometric structure of the Gravity Model. Using a single, unified and principled mechanism that is transparent enough to be generalized to other economic networks, the EGM allows trade probabilities and trade volumes to be separately controlled via any combination of dyadic and country-specific macroeconomic variables. We show that the EGM successfully reproduces both the topology and the weights of the ITN, finally reconciling the conflicting approaches. Moreover, it provides a general and simple theoretical explanation for the failure of economic models that do not explicitly focus on network topology: namely, their lack of topological invariance under a change of units.

Authority and Centrality: Power and Cooperation in Social Dilemma Networks

Date: 2015-03
By: Ramalingam, Abhijit
Rojo Arjona, David
Schram, Arthur
Van Leeuwen, Boris
We investigate the effects of power on cooperation in repeated social dilemma settings. Groups of five players play either multi-player trust games or VCM-games on a fixed network. Power stems from having the authority to allocate funds raised through voluntary contributions by all members and/or from having a pivotal position in the network (centrality). We compare environments with and without ostracism by allowing players in some treatments to exclude others from further participation in the network. Our results show that power matters but that its effects hinge strongly on the type involved. Reminiscent of the literature on leadership, players with authority often act more cooperatively than those without such power. Nevertheless, when possible, they are quickly ostracized from the group. Thus, this kind of power is not tolerated by the powerless. In stark contrast, centrality leads to less cooperative behavior and this free riding is not punished; conditional on cooperativeness, players with power from centrality are less likely to be ostracized than those without. Hence, not only is this type of power tolerated, but so is the free riding it leads to.
Keywords: power, cooperation, networks, public goods
JEL: C91 D02 D03 H41

Anonymous social influence

Date: 2013
By: Manuel Foerster (CES – Centre d’économie de la Sorbonne – CNRS : UMR8174 – Université Paris I – Panthéon-Sorbonne, CORE – Center of Operation Research and Econometrics [Louvain] – Université Catholique de Louvain (UCL) – Belgique)
Michel Grabisch (CES – Centre d’économie de la Sorbonne – CNRS : UMR8174 – Université Paris I – Panthéon-Sorbonne, EEP-PSE – Ecole d’Économie de Paris – Paris School of Economics – Ecole d’Économie de Paris)
Agnieszka Rusinowska (CES – Centre d’économie de la Sorbonne – CNRS : UMR8174 – Université Paris I – Panthéon-Sorbonne, EEP-PSE – Ecole d’Économie de Paris – Paris School of Economics – Ecole d’Économie de Paris)
We study a stochastic model of influence where agents have “yes" or “no" inclinations on some issue, and opinions may change due to mutual influence among the agents. Each agent independently aggregates the opinions of the other agents and possibly herself. We study influence processes modeled by ordered weighted averaging operators, which are anonymous: they only depend on how many agents share an opinion. For instance, this allows to study situations where the influence process is based on majorities, which are not covered by the classical approach of weighted averaging aggregation. We find a necessary and sufficient condition for convergence to consensus and characterize outcomes where the society ends up polarized. Our results can also be used to understand more general situations, where ordered weighted averages are only used to some extent. Furthermore, we apply our results to fuzzy linguistic quantifiers, i.e., expressions like “most" or “at least a few".
Keywords: Influence; Anonymity; Ordered weighted averaging operator; Convergence; Consensus; Fuzzy linguistic quantifier

Either or Both Competition: A “Two-sided" Theory of Advertising with Overlapping Viewerships

Date: 2014-10-18
By: Attila Ambrus (Duke University)
Emilio Calvano (CSEF, Università di Napoli Federico II)
Markus Reisinger (Otto Beisheim School of Management)
In media markets, consumers spread their attention to several outlets, increasingly so as consumption migrates online. The traditional framework for studying competition among media outlets rules out this behavior by assumption. We propose a new model that allows consumers to choose multiple outlets and use it to study the effect of strategic interaction on advertising levels, and the impact of entry and mergers. We show that novel forces come into play, which reflect the outlets’ incentives to control the composition of the customer base in addition to its size. We link consumer preferences and advertising technologies to market outcomes. The model can explain a number of empirical regularities that are difficult to reconcile with existing models.
Keywords: Media Competition, Two-Sided Markets, Multi-Homing, Viewer Composition, Viewer, Preference Correlation
JEL: D43 L13 L82 M37

Open Access vs. Restricted Access with Two Variable Factors: On the Redistributive Effects of a Property Regime Change

Date: 2014
By: Ronan Congar
Louis Hotte
We consider the factor payment effects of a transition from open access to restricted access in the resource sector in the long-run, i.e., when both labor and capital are mobile between sectors. We show that the transition benefits (harms) the factor that is initially used more (less) intensively in the manufacturing sector relative to the resource sector. Our analysis introduces a dual approach used to compare equilibria between property regime types.
Keywords: Property Rights, Natural Resources, Mobile Capital, Factor Payments, Income Distribution, Dual Approach.
JEL: D02 D23 D33 K11 Q2 N5 O13

Sequential selling and information dissemination in the presence of network effects

Date: 2014-10
By: Junjie Zhou (School of International Business Administration, Shanghai University of Finance and Economics, 777 Guoding Road, Shanghai, 200433, China)
Ying-Ju Chen (School of Business and Management & School of Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong)
In this paper, we examine how a seller sells a product/service with a positive consumption externality, and customers are uncertain about the product’s/service’s value. Because early adopters learn this value, we consider the customers’ intrinsic signaling incentives and positive feedback effects. Anticipating this, the seller commits to provide price discounts to the followers, and charges the leader a high price. Thus, the profit-maximizing pricing features the cream skimming strategy. We also show that the lack of seller’s commitment is detrimental to the social welfare; nonetheless, the sequential selling still boosts up the seller’s profit. Embedding a physical network with arbitrary payoff externality among customers, we investigate the optimal targeting strategy in the presence of information asymmetry. We provide precise indices for this leader selection problem. For undirected graphs, we should simply choose the player with the highest degree, irrespective of the seller’s commitment power. Going beyond this family of networks, in general the seller’s commitment power affects the optimal targeting strategy.
Keywords: revenue management; signaling; information transmission; social networks;
JEL: D82 L14 L15