A question for the research team perhaps:

When I explore the World Bank Data there are often transactions which are 'Loan Repayments' and 'Interest Repayments' but are negative values.

Does a figure of £-100 in Loan Repayments mean that the transaction shows when the country paid back the World Bank, or does it show that the world bank has given the county £100 in that transaction (though as a loan rather than a grant). So that, for example, I could generate a figure of 'Outstanding loans' by taking the inverse of Loan Repayments recorded in the file...

Also, how should these be factored in to any calculations on the total 'aid' a country has received? Are there any rules that can be applied to analysing these sums? 

(For example, once a project status is completed, you can sum up in some way loans and interest to get a figure for aid recieved).

Or should loans always be considered separately?