Diversité des approches de modélisation statistique en analyse de réseaux sociaux multiniveaux

Cet article présente différentes approches statistiques combinant l’analyse multiniveau et l’analyse de réseaux sociaux, allant des modèles p2 multiniveau pour l’analyse de données de réseaux égocentrées aux Exponential Random Graph Models (ERGM) pour des données multiniveaux néostructurales. Nous développons premièrement les modèles stochastiques basés sur une dépendance dyadique, intégrant l’approche hiérarchique par une mise en parallèle de différentes expériences. Après avoir présenté la modélisation de type ERGM, nous nous demandons explicitement comment introduire de la dépendance « multiniveau » dans ces derniers. Nous terminons alors sur la formalisation proposée par Robins et Wang [2010] qui semble la plus aboutie pour traiter la dépendance verticale entre ces deux réseaux de niveaux différents, mais partiellement emboités

Interdependent policy instrument preferences: a two-mode network approach

In policymaking, actors are likely to take the preferences of others into account when strategically positioning themselves. However, there is a lack of research that conceives of policy preferences as an interdependent system. In order to analyse interdependencies, we link actors to their policy preferences in water protection, which results in an actor-instrument network. As actors exhibit multiple preferences, a complex two-mode network between actors and policies emerges. We analyse whether actors exhibit interdependent preference profiles given shared policy objectives or social interactions among them. By fitting an exponential random graph model to the actor-instrument network, we find considerable clustering, meaning that actors tend to exhibit preferences for multiple policy instruments in common. Actors tend to exhibit interdependent policy preferences when they are interconnected, that is, they collaborate with each other. By contrast, actors are less likely to share policy preferences when a conflict line divides them

The shortest distance in random multi-type intersection graphs

Using an associated branching process as the basis of our approximation, we show that typical inter-point distances in a multitype random intersection graph have a defective distribution, which is well described by a mixture of translated and scaled Gumbel distributions, the missing mass corresponding to the event that the vertices are not in the same component of the graph.Comment: 32 page

Social Capital, Networks and Interlocking Directorates: A Mexican Case

Purpose ? This paper investigates whether a pattern of interlocking directorates is emerging following reforms in Mexican corporations, and who, if any, are the powerful actors in this network. Drawing on the Bourdieusian notion of social capital, the paper also analyses theoretically the interlocking directorates, networks and powerful actors, and their influences on and potential implications for corporate governance mechanisms. Design/methodology/approach ? The data used in the study consisted of 1,442 internal and external board members of the population of 126 Mexican corporations trading on the Mexican Stock Market as of January 2011. Use of social network analysis (SNA) demonstrates individuals? links with corporations and allows the production of spatial maps to visualise the network structure of interlocking boards. Findings ? Using the measures of SNA developed by Freeman (1979), we identify the most powerful and influential directors in the network structure of board members in Mexico. Board members with the greatest number of connections occupy central positions in the network. We also find a catalogue of corporate governance scandals. The inclusion of independent directors seems to have had no influence in ensuring better corporate governance. Research limitations/implications ? Mapping out the directors? links might offer excellent opportunities for policy makers to see how many companies a single director represents, how they share boards, and the implications for minority shareholders of sharing boards, and to understand the workloads of directors in carrying out the monitoring tasks expected of them. Originality/value ? This paper makes an important contribution by employing SNA to illustrate interlocking directorates and the positions of powerful and influential actors. Examining networks of directors from a ?social capital? point of view also provides an understanding of why the role of independent directors remains toothless in family-dominated corporations

Using Affiliation Networks to Study the Determinants of Multilateral Research Cooperation Some empirical evidence from EU Framework Programs in biotechnology

This paper studies multilateral cooperation networks among organizations and work on a two-mode representation to study the decision to participate in a consortium. Our objective is to explain the underlying processes that give rise to multilateral collaboration networks. Particularly, we are interested in how heterogeneity in organizations' attributes plays a part and in the geographical dimension of this formation process. We use the data on project proposals submitted to the 7th Framework Program (FP) in the area of Life sciences, Biotechnology and Biochemistry for Sustainable Non-Food. We employ exponential random graph models (p* models) (Frank and Strauss, 1986 ; Wasserman and Pattison, 1996) with node attributes (Agneessens et al., 2004), and we make use of extensions for affiliation networks (Wang et al., 2009). These models do not only enable handling variability in consortium sizes but also relax the assumption on tie/triad independence. We obtained some preliminary results indicating institutional types as a source of heterogeneity affecting participation decisions. Also, these initial results point out that organizations take their potential partners' participations in other projects into account in giving their decision ; organizations located in the core European countries tend to participate in the same project ; the tendency to preserve the composition of a consortium across projects and the tendency of organizations with the same institutional type to co-participate are not significant

De la relación inter-individual a la relación inter-organizacional : un análisis de redes multinivel de un mercado de programas de televisión en África subsahariana

Hoy, el encastramiento de las actividades económicas en las relaciones sociales no parece ser un hecho a demostrar en el campo de la sociología económica. Sin embargo, ¿podemos concluir que un contrato comercial entre dos empresas está necesariamente encastrado en las relaciones sociales de sus miembros? Sobre la base de los conceptos de encastramiento y desacoplamiento de White, intentaremos analizar cómo las relaciones inter-individuales pueden convertirse en relaciones inter-organizacionales. El análisis de redes sociales multinivel constituye un marco teórico y metodológico para captar este fenómeno. Describiremos a través del estudio de una red multinivel de un salón de distribución de programas audiovisuales en África, la dinámica entre encastramiento y desacoplamiento que podemos observar en un mercado. Demostramos que en la medida en que los individuos participan más en este salón, más serán los contratos entre las empresas que están encastrados en sus redes.L'encastrement des activités économiques dans les relations sociales ne semble plus aujourd'hui un fait à prouver dans le champ de la sociologie économique. Pourtant, pouvons-nous en conclure qu'un contrat commercial entre deux entreprises est nécessairement encastré dans les relations sociales de leurs membres ? En nous inspirant des concepts d'encastrement et découplage de White, nous chercherons ainsi à analyser comment des relations inter-individuelles peuvent devenir des relations inter-organisationnelles. L'analyse de réseaux sociaux multiniveaux constitue un cadre théorique et méthodologique permettant de saisir ce phénomène. Nous décrirons ainsi à travers une étude de réseau multiniveaux d'un salon de distribution de programmes audiovisuels en Afrique, les dynamiques entre encastrement et découplage observables sur un marché. Nous montrons entre autres que plus les individus participent à ces salons, plus les contrats entre leurs entreprises sont encastrés dans leurs réseaux