What Explains the Quantity and Quality of Local Inventive Activity?

The authors geocode a data set of patents and their citation counts, including citations from abroad. This allows them to examine both the quantity and quality of local inventions. They also refine their data on local academic RD With one important exception, results using citation-weighted patents are similar to those using unweighted patents. For example, estimates of the returns to density (jobs per square mile) are only slightly changed when using citation-weighted patents as the dependent variable. But estimates of returns to city size (urbanization effects) are quite sensitive to the choice of dependent variable. ; Local human capital is the most important determinant of per capita rates of patenting. A 1 percent increase in the adult population with a college degree increases the local patenting rate by about 1 percent. ; With few exceptions, there is little variation across fields of science in the contribution of academic RD They discuss the implications of these results for policy and future research.