The most powerful factor in economic growth is human capital - the level and concentration of skilled, energetic, and productive people. Charting the human capital levels of nations and regions is all the rage today, but Adam Smith long ago argued that human capital constitutes a critical fourth factor of production alongside land, labor, and capital. Human capital is the key factor in both national and regional growth, according to careful empirical studies.
Most regional economic analyses measure human capital across metropolitan regions. But metro regions - which are made up of central cities and their surrounding suburbs - come in all kinds of shapes and sizes. Some have densely concentrated central cities, like Manhattan in the greater New York region; others are more continuously sprawling like Los Angeles. A while back, a reporter called to ask me about the role of human capital in Milwaukee. He wanted to know whether it made any difference that human capital levels were low in the central city compared to the region as a whole. I responded that I thought it did. Following Jane Jacobs, my hunch was that regions with more concentrated human capital would have some advantage over others where the distribution was flatter or more similar across the metro. When his article came out, a number of prominent economists more or less said the same thing. But we all added that we couldn't be sure; most studies focus on human capital at the metro level and few, if any, have looked at the distribution of human capital within metros - that is, between the urban center and its suburbs.