RT Journal Article SR Electronic T1 Controversy, Facts and Assumptions JF African Economic History JO Afr Eco His FD University of Wisconsin Press SP 104 OP 136 DO 10.3368/aeh.46.1.104 VO 46 IS 1 A1 JERVEN, MORTEN YR 2018 UL https://aeh.uwpress.org/aeh.uwpress.org/content/46/1/104.abstract AB This article contributes to the debates surrounding “New African Economic History” by exploring the feasibility of constructing a time series of economic growth in Nigeria spanning the whole twentieth century. Currently most datasets for African economies only go back to 1960. The sources for their creation exist, but these valuable colonial data remain underutilized. This is an exploratory paper in a project aiming to create measures of economic growth through the twentieth century for a sample of African economies. The paper offers a systematic discussion of the different available datasets on population, agricultural production and income for the country. It finds that the existing data, often presented as facts, are more accurately described as projections based on assumptions. If these assumptions are already made in the production of the data, this precludes empirical testing of important questions. The main lesson is that any African economic history investigation must both begin and end with a critical analysis of the quantitative data, and must further be supported by careful qualitative evaluation.