Most obviously, urban population grows, in part fuelled by migration out of rural areas. Less obvious is that countries undergoing economic and geographical transformations are usually experiencing a demographic transition from high to low rates of birth and death, during which population grows rapidly. A slowing of population growth as the demographic transition proceeds accompanies structural transformation. Dependency ratios fall so that the share of the population in working age rises: a demographic dividend that applies until the population begins to age (Eastwood & Lipton 2012, Timmer 2009).

All of today’s high-income and middle-incomes countries have seen these changes, whether they be the early industrialisers of the eighteenth century, or the more recent emerging economies where industrialisation has taken place in the last fifty or so years.

What drives these changes?

Structural change is both a result of economic growth and a cause of it.