We examine sources of productivity in bioscience research and graduate training in U.S. universities. For this purpose, we first identify the scientific publications cited on agricultural biotechnology patents, and then trace the citations back to the universities producing the cited research....

The average quality of agricultural biotechnology patents appears to have declined substantially during the past two decades. This quality deterioration may reflect either a decline in the significance of new inventions or an increased use of patents as "protective thickets" against competitors'...