Patents: Recent Trends and Puzzles

This paper reviews the historical data on patenting in the United States with special reference to the last 20 years and their potential relation, if any, to the recent productivity slowdown. Two Points are made: Patents are not a "constant-yardstick" indicator of either inventive input or output. Moreover, they are "produced" by a governmental agency which goes through its own budgetary and inefficiency cycles. The paper shows that the appearance of an absolute decline in patenting in the 1970's is an artifact of such a cycle. This leaves us still with the longer run puzzle of a slower growth in patenting, especially by U.S. residents, relative to R&D expenditures. It is conjectured that this reflects more the changing character of patents and R&D than an indication of diminishing returns to R&D and an exhaustion of technological opportunities.