Distinguishing social mechanisms of membership adoption in emerging technology communities.

Digital platforms that enable and foster associations and sharing among entrepreneurs and knowledge workers have become a vital part of the new knowledge economy, yet we know little about the new form of social organization of knowledge. This paper seeks to explore and evaluate two microscopic social mechanisms, namely network effect of recruitment and cultural affinity, that may produce knowledge clustering and differentiation within these communities. To understand the relative effect of mechanisms, we develop a novel estimation procedure that matches individual users based on their historical behavioral patterns.

Association Between Degrees of Separation in Physician Networks and Surgeons' Use of Perioperative Breast Magnetic Resonance Imaging.

Background: Perioperative magnetic resonance imaging (MRI) is frequently used in breast cancer despite unproven benefits. It is unclear whether surgeons' use of breast MRI is associated with the practices of other surgeons to whom they are connected through shared patients.

Methods: We conducted a retrospective study using Medicare data to identify physicians providing breast cancer care during 2007-2009 and grouped them into patient-sharing networks.

Innovation or deviation? The relationship between boundary crossing and audience evaluation in the music field.

Prior research in organizations has shown that the spanning of distinct social categories usually leads to an unfavorable reaction from the audience. In the music field, however, a recombination of categories has long been celebrated as a major source of innovation. In this research, we conduct a systematical research on the effect of spanning behavior by musicians with a particular focus on the structural heterogeneity of categorical boundaries.

Measuring structural similarity in large online networks.

Structural similarity based on bipartite graphs can be used to detect meaningful communities, but the networks have been tiny compared to massive online networks. Scalability is important in applications involving tens of millions of individuals with highly skewed degree distributions. Simulation analysis holding underlying similarity constant shows that two widely used measures - Jaccard index and cosine similarity - are biased by the distribution of out-degree in web-scale networks.

Why Do Liberals Drink Lattes?

Popular accounts of "lifestyle politics" and "culture wars" suggest that political and ideological divisions extend also to leisure activities, consumption, aesthetic taste, and personal morality. Drawing on a total of 22,572 pairwise correlations from the General Social Survey (1972-2010), the authors provide comprehensive empirical support for the anecdotal accounts. Moreover, most ideological differences in lifestyle cannot be explained by demographic covariates alone.