Diversity and Popularity in Social Networks

Homophily, the tendency of linked agents to have similar characteristics, is an important feature of social networks. We present a model of network formation that allows the meeting process to depend on individuals types and study the impact of such a bias on the network structure. Our main results fall into three categories: (i) we show how, at the group level, homophily depends on the groups size and the parameters of the formation process, (ii) we understand precisely the determinants of local homophily at the individual level, and (iii) we compare the distributions of intra- and inter-group links in terms of stochastic dominance. Especially, we find that popular individuals have more diverse social networks. Our results are supported empirically in the AddHealth data looking at networks of social connections between boys and girls.