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"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]

Abstract
Consumers, businesses, and organizations rely on others' ratings of items when making choices. However, individual reviewers vary in their accuracy and some are biased – either systematically over- or under-rating items relative to others' tastes, or even deliberately distorting a rating. We describe how to process ratings by a group of reviewers over a set of items and evaluate the individual reviewers' accuracies and biases, in a way that yields unbiased and consistent estimates of the items' true qualities. We provide Monte Carlo simulations that showcase the added value of our technique even with small data sets, and we show that this improvement increases as the number of items increases. Revisiting the famous 1976 wine tasting that compared Californian and Bordeaux wines, accounting for the substantial variation in reviewers' biases and accuracies results in a ranking that differs from the original average rating. We also illustrate the power of this methodology with an application to more than forty-five thousand ratings of "en primeur" Bordeaux fine wines by expert critics. Those data show that our estimated wine qualities significantly predict prices when controlling for prominent experts' ratings and numerous fixed effects. We also find that the elasticity of a wine price in an expert's ratings increases with that expert's accuracy.

Cet article présente un modèle théorique permettant d'établir, pour plusieurs classes de fonctions de valorisation des citations reçues par les articles, des relations de dominance entre les productions scientifiques d'établissements de recherche pris deux à deux. Ces relations de dominance sont ensuite utilisées pour construire des réseaux de dominance, des classements et des classes de référence. L'article discute les résultats obtenus pour les principales universités de recherche américaines.

In this paper, we make an exploratory use of computational 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 (Jackson, M.O., Wolinski, A., 1996. A strategic model of social and economic networks. Journal of Economic Theory 71, 44–74). This approach allows us to observe and discuss inefficiencies that arise in a strategic network formation context with imperfectly link-mediated positive externalities to connections and spatial link costs. Our results highlight that, depending on the strength of the externalities, emergent and efficient networks may share several structural properties. Nevertheless, emergent networks are insufficiently dense and should be more structured around central agents.