Models of New Product Diffusion Through Advertising and Word-of-Mouth

A model of the diffusion process is developed which recognizes (1) the interaction between adopters and non-adopters and (2) the influence of external information sources such as advertising. The model is extended by incorporating the effects of repeat purchasing. The models written by the following authors are shown to be special cases of this model: Gould. Nerlove and Arrow, Vidale and Wolfe, Palda, Bass, Nicosia, and Glaister. The behavioral assumptions which support the model are made explicit and the implications of these assumptions for the shape of the new product growth curve are derived.