Two innovations in the last century have changed dramatically the cost of communicating and transmitting information: The first is the widespread adoption of telephony; the second is the internet. We study the implications of these changes in ICT for urban structure. We find robust evidence that...

The confluence of factors driving urban growth is highly complex, resulting from a combination of ecological and social determinants that co-evolve over time and space. Identifying these factors and quantifying their impact necessitates models that capture both why urbanization happens as well...

In this paper we show that the recent model by Duranton (AER, 2007) performs remarkably well in replicating the city size distribution of West Germany, much better than the simple rank-size rule known as Zipf's law. The main mechanism of this theoretical framework is the churning of industries...

Urban spatial structures are shaped by market forces interacting with regulations, primary infrastructure investments and taxes. They are usually the unintended result of unforeseen consequences of policies and regulations that were designed without any particular spatial concerns. However,...

The salient rank-size rule known as Zipf's law is not only satisfied for Germany's national urban hierarchy, but also for the city size distributions in single German regions. To analyze this phenomenon, we build on the insights by Gabaix (1999) that Zipf's law follows from a stochastic growth...