Is it what we do or how we do it? New evidence on agglomeration economies and metropolitan growth

This paper uses data on U.S. metropolitan areas from 1970 to 1999 to examine the extent to which recent increases in earnings are attributable to agglomeration economies. We decompose the total change in earnings over the 19701999 period into components attributable to changes in relative growth, industry mix and interaction effects. We find strong evidence that relative growth matters more than industry mix. In addition, we find that relative growth effects are related to both localization and urbanization economies.