Aid, if it achieves the UN’s goals, is often saving the lives of the poorest. In this respect, we can say aid has been successful. And it is this very success that could explain why we don’t see any effect on growth. In fact, for the first few decades of aid, it’s conceivable that it would appear to reduce per capita income growth.
If aid saves the lives of millions of poor infants, or mothers in childbirth, at roughly the same rate a country can industrialize, then we’ll see an increase in the number of poor people at about the same rate that we increase GDP per person. Unless aid is also spurring faster industrial growth, the growth figures essentially won’t change. The things that aid does well–increasing primary education, saving lives, and leading to a demographic transition (essentially lower population growth–may reasonably take a generation or two to impact industry.
So if aid has been good at saving lives now, but not (in the short term) at spurring industry, then we shouldn’t be surprised that we don’t see take-offs. Rather, in most countries aid might actually lower the short term, measured number.
But by almost any measure, though, aid would still be a huge success. Maybe the “failure of aid” is really a failure to industrialize, disguised.
The link is here. Lately I've been trying to think through the opposite point. How many uninsured do they have in China? Over a billion? Letting a lot of sick people die, or simply not treating them much, can help your per capita growth statistics. If you don't take individual preferences to have value in their own right, but simply wish to maximize measured growth per capita, you'll value human life at something like replacement cost.