In 2007, the world reached an important “tipping point”—half its
population became urban. But not only is the world urbanising, it has
been doing so much more rapidly. While it took Industrial Europe 110
years (1800-1910) to increase its rate of urbanisation from 15 to 40 percent,
Asia and Africa did so twice as fast, in only 50 years (1960-2010). And
the urban population in the developing world is also concentrating, living
increasingly in a few large cities. This also holds true in Africa, which
already has a clear bimodal distribution of its urban population (Dorosh
and Thurlow, 2013). Nonetheless, barring some exceptions1
, the academic
literature and policy mindsets have been squarely focused on the aggregate
rate of urbanisation. They seldom go beyond the dichotomous rural-urban
distinction, thereby ignoring the distribution of the urban population
across cities of different sizes. Results from our research suggest, however,
that the composition of urbanisation might be as important as its
aggregate rate.