Agglomeration economies reflect proximity and are an important explanation for industrial location. They feature prominently in the theories of location, including intermediate inputs and labour of the new economic geography and knowledge spillovers in the new growth theory. However, while there...

Ellison and Glaeser's (1997) index of geographical concentration distinguishes between natural advantages and spillovers as a source of industrial agglomeration, but the well-known 'observational equivalence' means little is known about the relative importance of these. This paper uses the...