We examine two sets of economies, (19th century U.S. states and 20th century less developed countries) where growth rates are positively correlated with initial levels of development to document how these dynamic increasing returns operate. We find that open economies do not display a positive...

Historically, urban growth required enough development to grow and transport significant agricultural surpluses or a government effective enough to build an empire. But there has been an explosion of poor mega-cities over the last thirty years. A simple urban model illustrates that in closed...

Africa is urbanizing rapidly, and this creates both opportunities and challenges. Labor productivity appears to be much higher in developing-world cities than in rural areas, and historically urbanization is strongly correlated with economic growth. Education seems to be a strong complement to...

New, “big” data sources allow measurement of city characteristics and outcome variables higher frequencies and finer geographic scales than ever before. However, big data will not solve large urban social science questions on its own. Big data has the most value for the study of cities when...