tend to leak out more slowly than product development. Teece (1980) showed similar results on the diffusion of an administrative innovation. In researching the imitation cost and time for new innovations, Mansfield found that patent protection does not make entry impossible. In fact, within 4 years of their introduction, 60% of the patented successful innovations were imitated, Patent protection does, however, tend to increase the cost of imitation. The reader is cautioned
that these figures are somewhat industry dependent