 Engerman's 5% figure gives as much as possible in terms of benefit of the doubt to the Williams argument, not solely because it does not take into account the associated costs of the slave trade to Britain, but also because it carries the full-employment assumption from economics and holds the gross value of slave trade profits as a direct contribution to Britain's national income.Historian Richard Pares, in an article written before Williams' book, dismisses the influence of wealth generated from the West Indian plantations upon the financing of the Industrial Revolution, stating that whatever substantial flow of investment from West Indian profits into industry there occurred after emancipation, not before.However, each of these works focus primarily on the slave trade or the Industrial Revolution, and not the main body of the Williams thesis, which was on sugar and slavery itself.