The product life cycle model has been refined by the work of Abernathy and Utterback.7 Initially, in their framework, product design is fluid and substantial product variety is present. Product innovation is the dominant mode of innovation, and aims primarily at improving product performance instead of lowering cost. Successive product innovations ultimately yield a "dominant design" where the optimal product configuration is reached. As product design stabilizes, how- ever, increasingly automated production methods are employed, and process innovation takes over as the dominant innovative mode to lower costs. Ultimately, innovation of both types begins to slow down. Recently, the concept of "dematurity" has been added to the Abernathy8 frame- work to recognize the possibility that major technological changes can throw an industry back into a fluid state.