We examine the extent of diffusion of a new technology in two countries, asking why the point of saturation, the onset of stabilization or decline, occurred at different times. This longitudinal study relies on a comparative inductive methodology and primary archival data spanning 20 years. The context is the spread of prefabrication in the French and Danish construction industries 1945-1965. We find that interactions between theorization and objectification explain diffusion, and that socio-political legitimacy determines the extent of diffusion when cognitive legitimacy is high and pragmatic legitimacy low. Three differentiating features of socio-political legitimacy are technological selection, resource allocation, and administrative support.
