In 1991, I published in this journal estimates of the percentage of new products and processes based on recent academic research—that is, academic research occurring within 15 years of the commercialization of whatever innovation is being considered— in the drug and medical product, information processing, chemical, electrical, instruments, metals, and Ž . oil industries in 1975–1985 Mansfield, 1991, 1992 . Because there has been considerable interest in such estimates , I have gathered similar data from a sample of 77 major firms for 1986–1994, the only significant difference in the sample design being that the machinery industry, which is reasonably active in this regard, has been substituted for oil. 3 Table 1 shows that the overall results for 1986– 1994 are very similar to those for 1975–1985, although particular industries sometimes vary substantially, as one might expect. The industry means in
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