Homophily and prestige: An assessment of their relative strength to explain link formation in the online climate change debate

Previous work has shown that hyperlinks reflect actors' strategic choices; these dyadic relationships depend on the actors' exogenous attributes (e.g., homophily) and the network's endogenous features (e.g., prestige distribution among actors). We combine these factors as explanatory variables in different exponential random graph models (ERGMs) to assess the relative strength of prestige and homophily for the actors' link formation. We analyze the climate change discourse in a hyperlink network formed by US civil society actors from November 2014 and test how relevant the different factors are, including variables such as actor type, country, position, and topic. We find that both prestige and various aspects of homophily influence link formation online. With regard to the importance of the different factors, positional homophily stands out, followed by prestige and other homophily effects.