Domestic migration and city rank dynamics

Abstract

Recent studies show that rare and extreme domestic migration flows influence both population growth and the rise and fall of cities in urbanized countries such as the USA, Canada, the UK and France. This study examines the relationship between domestic net flows (inflows minus outflows) and city rank volatility across countries over time. We find that approximately 95% of cities, representing up to 99% of a country’s population, exhibit rescaled net flows that conform to normal distributions, while about 5% experience migration shocks. Small cities are more susceptible to these shocks, often caused by net flows from larger, nearby cities, while in France, large cities also experience shocks from smaller ones. We also show that domestic migration is an important component of population growth in small cities, thus explaining their rank volatility, and that the rank stability of large cities is supported by international migration and natural increase. This study characterized the intercity domestic migration flows in four countries, and found that in the USA, the UK and Canada, flows from big cities serve as shocks in smaller nearby cities, but not in France.