Knowledge flows and the geography of networks. A strategic model of small worlds formation.

This paper aims to demonstrate that the strategic approach of network formation can generate networks that share the main structural properties of most real social networks. We introduce a spatialized variation of the Connections model (Jackson and Wolinski, 1996) in which agents balance the benefits of forming links resulting from imperfect knowledge flows through bonds against their costs which increase with geographic distance. We show that, for intermediary levels of knowledge transferability, our time-inhomogeneous process selects networks which exhibit high clustering, short average distances and, when the costs of link formation are normally distributed across agents, skewed degree distributions.Strategic network formation ; Time-inhomogeneous process ; Knowledge flows ; Small worlds ; Monte Carlo simulations.

Who's Who in Patents. A Bayesian approach

This paper proposes a bayesian methodology to treat the who's who problem arising in individual level data sets such as patent data. We assess the usefullness of this methodology on the set of all French inventors appearing on EPO applications from 1978 to 2003.Patents; homonymy; Bayes rule

A strategic model of complex networks formation.

This paper introduces a spatialized variation of the Connections model of Jackson and Wolinski (1996). Agents benefit from their direct and indirect connections in a communication network. They are arranged on a circle and bear costs for maintaining direct connections which are linearly increasing with geographic distance. In a dynamic setting, this model is shown to generate networks that exhibit the small world properties shared by many real social and economic networks.Strategic Network Formation, Pairwise Stability, Small World, Monte Carlo.

The ‘problem of problem choice’: A model of sequential knowledge production within scientific communities cientific communities.

In this paper we present an original model of sequential problem choice within scientific communities. Disciplinary knowledge is accumulated by solving problems emerging in a growing tree-like web of research areas. Knowledge production is sequential since the problems solved generate new problems that may be handled. The model allows us to study how the reward system in science influences the scientific community in stochastically selecting at each period its research agendas, and the long term resulting disciplines. We present some evidence on a decrease in the generation of new areas, a path dependency in specialization, and circumstances under which collapsing dynamics arise.Sequential Problem Choice; Stochastic Process; Tree; Graph Theory; Scientific Knowledge; Academics; Reward System

The incentive properties of the Matthew Effect in the academic competition.

This paper is concerned with the incentive properties of the Matthew Effect by which since Merton [1968] one is usually describing the various cumulative advantages that obviously affect academic competition. We introduce a model of sequential contests in which the agents that have initially produced more are the ones that will be further advantaged in that they are benefiting from intrinsically more productive research positions. We principally show that there is an optimal level of the Matthew effect and that this optimal dynamic bias is increasing with the risk of research activity while it is decreasing with the initial inequalities.Matthew Effect, cumulative advantages, sequential contests, academic competition.

Why do Academic Scientists Engage in Interdisciplinary Research ?

This article provides a first empirical study of the determinants of the propensity to which academic scholars tend to perform interdisciplinarity research. For that purpose we introduce a measure of interdisciplinarity as the diversity of their research production across scientific domains. Our dataset concerns more than nine hundred permanent researchers employed by a large French university which is ranked first among French universities in terms of Impact. As expected we find that the traditional academic career incentives do not stimulate interdisciplinary research while having connections with industry does. The context of work in the laboratory (size, colleagues’ status, age and affiliations) strongly affects the propensity to undertake interdisciplinary research.Economics of science, Academic incentives, Interdisciplinary research, Laboratory, University.

Dominance relations when both quantity and quality matter, and applications to the\r\ncomparison of US research universities and worldwide top departments in economics

In this article, we propose an extension of the concept of stochastic dominance intensively\r\nused in economics for the comparison of composite outcomes both the quality and the\r\nquantity of which do matter. Our theory also allows us to require unanimity of judgement\r\namong new classes of functions. We apply this theory to the ranking of US research\r\nuniversities, thereby providing a new tool to scientometricians (and the academic\r\ncommunities) who typically aim to compare research institutions taking into account both\r\nthe volume of publications and the impact of these articles. Another application is provided\r\nfor comparing and ranking academic departments when one takes into account both the size\r\nof the department and the prestige of each member.Ranking, dominance relations, citations.

Coordination failures in network formation.

In this paper, we make an exploratory use of numerical techniques (genetic algorithms and Monte Carlo simulations) to compute efficient and emergent networks in a spatialized version of the connections model of Jackson and Wolinski (1996). This approach allows us to observe and discuss the coordination failures that arise in a strategic network formation context with link-mediated positive externalities to connections and geographically based connection costs. Our results highlight that, depending on the strength of the externalities, emergent and efficient networks may share several structural properties. Nevertheless, emergent networks have too few local and distant connections and are also too less “coordinated” around some central agents than they should.Strategic Network Formation; Efficiency; Stability; Coordination; Small Worlds; Genetic Algorithms; Monte Carlo Simulations.

Self-Organizing Innovation Networks: When do Small Worlds Emerge?

In this paper, we present a model of 'collective innovation' built upon the network formation formalism. In our model, agents localized on a circle benefit from knowledge flows from other agents with whom they are directly or indirectly connected. They support costs for direct connections which are linearly increasing with geographic distance. The dynamic process of network formation exhibits prefeRential meeting for close agents (in the relational network and in the geographic metrics). We show how the set of stochastically stable networks selected in the long run is affected by the degree of knowledge transferability. We find critical values of this parameter for which stable \"small world\" networks are dynamically selected.Network Formation, Stochastic Stability, Preferential Meeting, Self-Organization,

Knowledge flows and the geography of networks: a strategic model of small world formation

"This paper aims to demonstrate that the strategic approach to link formation can generate networks that share some of the main structural properties of most real social networks. For this purpose, we introduce a spatialized variation of the Connections model (Jackson and Wolinsky 1996) to describe the strategic formation of links by agents who balance the benefits of forming links resulting from imperfect knowledge flows against their costs, which increase with geographic distance. We show, for intermediate levels of knowledge transferability, clustering occurs in geographical space and a few agents sustain distant connections. Such networks exhibit the small world property (high clustering and short average relational distances). When the costs of link formation are normally distributed across agents, asymmetric degree distributions are also obtained." [author's abstract