We know less about growth and poverty based on numbers in African economies than we would like to think. Numbers are soft, and data availability is sparse, sporadic, and uneven. For researchers and data users, whether engaged in inferential or descriptive statistics, the message is that studying Africa by numbers can be misleading. This research note surveys the knowledge gap and provides guidance on how to and how not to study Africa by numbers. ON 5 NOVEMBER 2010, Ghana Statistical Services announced new and revised GDP estimates. As a result, the estimated size of the economy was adjusted upward by over 60 percent, suggesting that in previous GDP estimates economic activities worth about US$13 billion had been missed. While this change in GDP was exceptionally large, it did not turn out to be an isolated case. On 7 April 2014, the Nigerian Bureau of Statistics declared new GDP estimates. GDP was revised upward to $510 billion, an 89 percent increase from the old estimate. These well-publicized statistical events have led to an increase in the attention being paid to the quality of macroeconomic statistics in low-income countries, especially in African countries. The concurrent large and seemingly abrupt changes in GDP have led to a reconsideration of the quality of the data needed to evaluate basic trends in growth and poverty. At the same time, according to the African Development Bank, such substantial *Morten Jerven (morten.jerven@nmbu.no) is Associate Professor in Global Change and International Relations at the Norwegian University of Life Sciences. 1. Morten Jerven, ‘For richer, for poorer: GDP revisions and Africa’s statistical tragedy’, African Affairs 112, 446 (2013), pp. 138–47. 2. Morten Jerven, ‘What does Nigeria’s new GDP number actually mean?’, African Arguments, 7 April 2014, (12 January 2016). African Affairs, 115/459, 342–358 doi: 10.1093/afraf/adw006 © The Author 2016. Published by Oxford University Press on behalf of Royal African Society. All rights reserved Advance Access Publication 31 March 2016