In the study of complex networks, assortative mixing, or assortativity, is a bias in favor of connections between network nodes with similar characteristics. In the specific case of social networks, assortative mixing is also known as homophily. The rarer disassortative mixing is a bias in favor of connections between dissimilar nodes. Assortative mixing is also observed in other (non-social) types of networks, including biochemical networks in the cell, computer and information networks, and others.