Using a panel data set of county-level employment in machinery, electrical machinery, primary metals, transportation, and instruments, this paper analyzes the role of dynamic externalities for individual industries. Key issues examined include the role of externalities from own industry...

Using extensive data on 1970 and 1987 urban characteristics, the paper analyzes changes in employment in specific manufacturing industries in cities between 1970 and 1987. Two sets of questions are the focus. First, what present or past characteristics of a city's economic environment are...