Demand Pull Models: Rothwell argues that in the latter half of the 1960s, empirical studies of
innovation processes began to emphasize market theories of innovation. These were again linear in nature, stressing
the role of the marketplace and market research in identifying and responding to customer needs, as well as directing
R&D investments towards these needs. In these models, the marketplace was the chief source of ideas for R&D and
the role of R&D was to meet market demands (Hobday, 2005).