In this paper we reinterpret the location quotient, the commonly employed measure of regional industrial agglomeration, as an estimator derived from Ellison and Glaeser [Ellison, G., and Glaeser, E., 1997. Geographic concentration in U.S. manufacturing industries: a dartboard approach. Journal...

This paper uses a novel approach and detailed plant-level Portuguese data to reexamine the Marshallian hypothesis that specialization and the vertical disintegration of firms should be greater in areas where an industry concentrates. Our measure of firm specialization and vertical disintegration...