We progress from the initial idea of there being urbanization processes of different quality, and analyze the growth of world cities over the period 1960-2000, attempting to find the factors behind the growth of "big" cities (Mega, Big and Midsize cities, in the UN classification). We use a new dataset with demographic, economic, institutional and geographic variables regarding almost 2,000 cities in 135 countries. The methodological approach is based on OLS cross-country analyses, and controls for collinearity. Results indicate that growth in very large agglomerations is linked to indicators of economic and institutional backwardness. Problems of reverse causality, that is, the effects of big urban agglomerations on long term economic growth, is not within the scope of our research. This question needs further research. .
Keywords: Urban agglomerations, economic growth, institutional quality.
Jel Code: 018, N90, R11, R12.