A comparative study of social network models: Network evolution models and nodal attribute models

This paper reviews, classifies and compares recent models for social networks that have mainly been published within the physics-oriented complex networks literature. The models fall into two categories: those in which the addition of new links is dependent on the (typically local) network structure (network evolution models, NEMs), and those in which links are generated based only on nodal attributes (nodal attribute models, NAMs). An exponential random graph model (ERGM) with structural dependencies is included for comparison. We fit models from each of these categories to two empirical acquaintance networks with respect to basic network properties. We compare higher order structures in the resulting networks with those in the data, with the aim of determining which models produce the most realistic network structure with respect to degree distributions, assortativity, clustering spectra, geodesic path distributions, and community structure (subgroups with dense internal connections). We find that the nodal attribute models successfully produce assortative networks and very clear community structure. However, they generate unrealistic clustering spectra and peaked degree distributions that do not match empirical data on large social networks. On the other hand, many of the network evolution models produce degree distributions and clustering spectra that agree more closely with data. They also generate assortative networks and community structure, although often not to the same extent as in the data. The ERGM model, which turned out to be near-degenerate in the parameter region best fitting our data, produces the weakest community structure.     

Unpacking the circular economy: A problematizing review

Transitioning to a circular economy (CE) model has been proposed to solve many grand environmental challenges. While research on CE has been extensively reviewed, less is known about the implicit underlying assumptions of this work. Understanding these assumptions is critical as they typically go unchallenged yet play a significant role in shaping research fields. In this paper we conduct a problematizing review to critically analyse and make explicit the in-house, root metaphor and ideological assumptions that inform the framing of CE. Firstly, we demonstrate various in-house assumptions about CE, such as an emphasis on the business case for CE and the relationship between CE and corporate sustainability. Secondly, root metaphor assumptions include circularity and industrial relationships resembling biological metabolisms. Finally, the dominant ideological assumptions-neoliberalism and ecological modernization-guide scholarly thinking about growth, consumption and profit maximization. Based on our analysis and drawing on the ongoing CE debates within broader environmental studies, we suggest new agendas for future research. We contribute to the growing literature on CE in business, management and organization studies by identifying assumptions that may be misleading or limiting for future CE research, as well as to the conversations on grand challenges by discussing the implications of how challenges and solutions are framed.