The standard approach to studying industrial agglomeration is to construct summary measures of the degree of agglomerationʺ within each industry and to test for significant agglomeration with respect to some appropriate reference measures. But such summary measures often fail to distinguish...

We employ a unique data set to examine the spatial clustering of about 1,700 private research and development (R&D) labs in California and across the Northeast corridor of the United States. Using these data, which contain the R&D labs' complete addresses, we are able to more precisely locate...