Homophily can act as an invisible barrier to the flow of innovations within a system. New ideas usually enter a system through higher status and more innovation members. A high degree of homophily would mean that these elite individuals interact mainly with one another, and thus the innovation would not trickle down to nonelites. Homophilous diffusion patterns cause new ideas to spread horizontally, rather than vertically, within a system. If homophily is a barrier to diffusion, change agents should work with several set of opinion leaders in a system. If the interpersonal networks in a system are characterized by a high degree of heterophily, a change agent could concentrate attention on only a few opinion leaders near the top in socioeconomic status and innovativeness (however, this is seldom the case).