Imagine you lived in a world where night lights from satellite images tell you instantly about the distribution and growth in economic activity and the extent and evolution in poverty. While such a world is probably still far off, night lights as observed from space are increasingly being used as a proxy of human economic activity to measure economic growth and poverty. In a fascinating 2012 paper in the American Economic Review, Henderson and colleagues found a strong correlation between growth in night lights as observed from space and growth in GDP, basedon data on 188 countries spanning 17 years. They use their estimates for two main purposes: (i) to improve estimates of “true” GDP growth in countries with weak statistical capacity and (ii) to estimate GDP growth at levels where national accounts are typically non-existent (sub-national or regional levels; coastal areas;,…).
The added value of such an approach for Africa is obvious. Most African countries rank low on the World Bank’s Statistical Capacity Indicators, with some countries lacking national accounts altogether. Some African countries are huge (in size), and having sub-national estimates of GDP growth would help identifying leading and lagging areas, and why. For a country such as Kenya, which is starting an ambitious decentralization project, the approach could estimate GDP growth for its 47 newly formed counties to help in their economic planning. Nightlights can even be used to show where the Pirates of Somalia are spending their ransom money.