The Roots of Agricultural Innovation: Evidence from Patents
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Chapter in forthcoming NBER book Economics of Research and Innovation in Agriculture, Petra Moser, editor
Agricultural productivity has increased tremendously over the last century, largely due to waves of technological innovations credited to past investment in agricultural research and development (R&D) activities. This paper investigates the extent to which knowledge spillovers from outside agriculture contribute to agricultural innovation. We develop metrics of US agricultural R&D output based on US patents granted over the period 1976-2016. To measure knowledge flows, we rely on three main proxies: patent citations to other patents, patent citations to the scientific literature, and a novel text analysis to identify and track new ideas in the patent text. The originating domain of knowledge flows is alternatively characterized in terms of patent technology classes, assignee area of research, and subject areas of scientific citations. We typically find more than half of knowledge flows originate outside of agriculture.