- 1950s-1960s Technology push:
Simple linear sequential process. Emphasis on R&D. The market is receptacle of the fruits of R&D, e.g. antibiotics.
- 1970s Market pull:
Simple linear sequential process. Emphasis on marketing. The market is the source of ideas for directing R&D. R&D has a reactive role.
- 1980-1985: Coupling model:
Sequential, but with feedback loops. Push or pull or push/pull combinations. R&D and marketing more in balance. Emphasis on integration at the R&D/marketing interface.
- 1985-1990s Integrated model:
Parallel development with integrated development teams. Strong upstream supplier linkages. Close coupling with leading edge customers, e.g. lead users (von Hippel, 1986). Emphasis on integration between R&D and manufacturing (design for make-ability). Horizontal collaboration (joint ventures etc). The growing importance of external knowledge for innovation reflects the academic literature, e.g. Absorptive capacity (Cohen and Levinthal, 1989).
- 2000 Network model:
Emphasis on external linkages.