Methodology

Africa’s Imperial Commodities uses available data on commodity exports to explore the history of African and European trade relationships. The data for the website comes from the African Commodity Trade Database (ACTD) published on the African Economic History Network as:

Frankema, Ewout, Jeffrey Williamson and Pieter Woltjer. “An Economic Rationale for the West African Scramble? The Commercial Transition and the Commodity Price Boom of 1835-1885.” The Journal of Economic History 78, no. 1 (2018): 231-267.

The most robust dataset from this site includes information on fourteen commodities moved between Africa and Europe between 1808 and 1939. There are more than nine thousand observations in the dataset, where each observation contains annual statistics for a single commodity. These statistics include information about the amount, cost, colony, and European nation. The ACTD was compiled from the Colonial Blue Books, the Statistical Abstracts for the United Kingdom, the Tableau General du Commerce de la France, and the Annual Statements of Trade for the United Kingdom. Data entry was completed by the Rural Environment History Group at Wageningen University.

Not every observation in the dataset, however, contains complete information about the cost or quantity of the commodity, for example. These omissions illustrate a challenge with creating a database from historical documents that differ by collection and even within the same collection may be inconsistent over long periods of time. Nonetheless, the database contains enough consistency whereby the publishers converted several different currencies into British pounds. They have also standardized non-metric units of quantity into kilograms, where possible.

The cost information tends to be more important for economic historians who measure the imbalance in trade terms as expressed by monetary values. Africa's Imperial Commodities focuses instead on the quantity of commodity exports and only includes observations with metric measurements. This decision limits the website's underlying data in important ways. For the 1,030 observations of animal hides and skins, 774 of them (75%) contain metric measurements. This creates a regional bias that reflects the different recording strategies in the source documents. For example, a majority of the animal hide observations for the Cape of Good Hope (99%) and all of those for Somalia do not include metric measurements. The essays in Africa's Imperial Commodities overcome this limitation by focusing on geographic areas with consistent observations.

The data on this website is saved as JSON files and was processed using R, a language for statistical analysis. The data visualizations were created using D3.JS, a JavaScript library.