The Upper Guinea Coast and the Trans-Atlantic Slave Trade Database

We are now better able to understand the impact of the slave trade on the evolution of the Atlantic world to a degree that could not have been imagined a generation ago, in a manner that might well fulfill the visions of Thomas Clarkson, W.E.B. Du Bois and other commentators.¹ Thus there is a long tradition of assessing patterns of the slave trade. Clarkson was using muster lists to determine voyage information, and at the same time abolitionists were gathering testimony on pathways of enslavement in Sierra Leone and elsewhere. Du Bois searched for comparable information a century later, but all this evidence is patchy. The Trans-Atlantic Slave Trade Database represents the culmination of inputting data into a common format that was collated by a team of scholars under the leadership of David Eltis, David Richardson and Paul Lachance. The first version of the database accounted for approximately 27,233 voyages and was published as a CDROM by Cambridge University Press in 1999, thirty years after the pioneering census by Philip D. Curtin that launched the modern study of the slave trade in 1969.² The current version accounts for more than 35,000 slaving voyages and has been available online (www.slavevoyages.org) since 2009.³ This version accounts for the overwhelming majority of voyages that carried enslaved Africans across the Atlantic. Its construction is an example of collaborative research at its best, drawing on the collective research of more than a dozen scholars over the past several decades.

The attempt to identify all voyages carrying Africans on ships across the Atlantic world is essential in determining where people came from in Africa and where they went, although tracking the ships is only one part of these much bigger questions of the types of research approaches that are necessary. In the case of the Trans-Atlantic Slave Trade Database, unprecedented recognition has almost given this database an identity of its own as “TSTD2,” that is the “transatlantic slave trade database 2,” although the title of the project significantly now emphasizes “voyages” and not “trade.” Nonetheless, TSTD2 has emerged as if it is a primary document(s) or a new persona of scholarship representing the collective input of many scholars, rather than a series of imputed variables. Inevitably, scholars will be examining the primary documentation behind TSTD2 and not rely on the imputed variables that underlay its construction. The Database has stimulated debate on a whole range of research issues, but in many ways the organisation of the data reflects the original priorities of the authors and the nature of the source material. A database is a tool that is used to organize data for purposes of analysis and is only as good as the imputations that underlay, which requires careful examination. This raises the issue of how to re-organise material, given that people with different interests will raise questions which are different to those originally raised by the compilers. In many ways, the existence of the Database has helped to frame new questions and identify new priorities.

This critique assesses some of the claims, methods, contributions, and also lapses of the Slave Trade Database from the perspective of African economic and social history and therefore addresses one of the issues that the Slave Trade Database addresses – the origins of people in Africa. There are alternate ways of organizing data, and inevitably in the digital age alternate approaches to identifying, searching and structuring data are being explored, partly in response to the collaborative effort behind the TSTD2, which has become the reference. My critique arises from a workshop that was held at the Harriet Tubman Institute, York University in 2010, and whose essays are the basis of this special edition of African Economic History. This essay is intended to explore and critique the interface between the Slave Trade Database and African economic history, and by implication, African social history. What can and what cannot be said in relation to the trans-Atlantic migration under slavery is crucial to the reconstruction of African history and the history of...