Relationship amongst technological substitution models of innovation diffusion

The two following types of relationships amongst different technological substitution models of innovation diffusion will be considered: (i)where one model may be a special case of another model, in the sense that the resulting model can be obtained by giving particular values to one or more parameters of the source model, or where the end model may be a limiting case of the source model, when parameter(s) in the source model approach particular values: and (ii)where one model may be obtained by transforming either a dependent or an independent variable in the source model. The concept of equivalent models is introduced, and it is shown that the models incorporating price structure or a variation of diffusion with space can be equivalent to the classical innovation diffusion models. This concept also leads to the development of a two-parameter general adoption model, and it is shown that this general model represents most of the well-known existing models as special cases. The usefulness of the general model is also presented.