Official development assistance, or ODA, has long been used to measure aid flow from bilateral donors to recipient countries.
But the way it is reported makes it difficult to gauge how much of it is directed towards development in low- and middle-income countries.
As a result, the Organisation for Economic Co-operation and Development, which sets the standard for ODA, developed a new method in 2007, to have a better estimate of the amount of money that flows into recipient countries.