SPATIAL AND TEMPORAL HETEROGENEITY IN-DIFFUSION

Standard models of diffusion assume spatial and temporal homogeneity. This article develops a class of diffusion models that incorporate spa tial and temporal heterogeneity by turning to the individual level wit hin an event-history framework. These models permit the analyst to rep resent social structural relations thought to channel diffusion, and t o model decay in the influence of events over time. Heterogeneous diff usion models are applied to a reanalysis of data reported in Coleman, Katz, and Menzel's classic diffusion study. Network centrality and loc al structures of influence based on cohesive relations and structural equivalence are all shown to channel the diffusion of tetracycline.