The evolution of the US urban structure from a long-run perspective (1900-2000)

This paper analyses the evolution of the size distribution of cities in the United States throughout the 20th century. In particular, we are interested in testing the fulfilment of two empirical regularities studied in urban economics: Zipf’s law, which postulates that the product between rank and size of a population is constant, and Gibrat’s law or the law of parallel growth, according to which the growth rate of a variable is independent of its initial size. For this parametrical and non-parametrical methods have been used. These laws have already been studied for the American case with the most populous cities or with MSAs. The main contribution of this work is the use of a new database with information on all the cities, thus covering the entire distribution. The results show that although if the sample is considered as a whole the fulfilment of Zipf’s law is rejected, Gibrat’s law is accepted for all the period considered.