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...

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...

The paper decomposes a geographical concentration index to examine the temporal scope of a spillover, which is the period of time over which one firm's activity directly affects the location of other firms' activities. Natural advantages are fixed over reasonably long time periods, but if...

The paper decomposes a geographical concentration index to examine the temporal scope of a spillover, which is the period of time over which one firm’s activity directly affects the location of other firms’ activities. Natural advantages are fixed over reasonably long time periods, but if...