UNU-MERIT Working Papers Series
Top Lights: Bright cities and their contribution to economic development
Richard Bluhm & Melanie Krause #2018-041Tracking the development of cities in emerging economies is difficult
with conventional data. We show that satellite images of nighttime
lights are a reliable proxy for economic activity at the city level,
provided they are first corrected for topcoding. The commonly-used data
fail to capture the true brightness of many cities. We present a
stylized model of urban luminosity and empirical evidence which both
suggest that these 'top lights' can be characterized by a Pareto
distribution. We then propose a simple correction procedure which
recovers the full distribution of city lights. Our results show that the
brightest cities account for nearly a third of global economic activity.
Applying this approach to cities in Sub-Saharan Africa, we find that
primate cities are outgrowing secondary cities but are changing from
within. Poorer neighborhoods are developing, but sub-centers are forming
so that Africa's largest cities are also becoming increasingly
fragmented.
JEL Classification: O10, O18, R11, R12
Keywords: Development, urban growth, night lights, top-coding,
inequality
Download the working paper (PDF)
