At Crooked Timber John Quiggin neatly summarises one of the essential facts of aid:
On the other hand, it has to be conceded that the record of non-military aid and public good promotion is not exactly one of stellar success either. The fact is that the world is a complicated and intractable place, and running your own country is hard enough – the fact that international efforts work as well as they do is more surprising than the fact that so many fail.
The shortcomings of some aid endeavours are beyond the pale – boomerang aid; aid that is used to buy influence with little concern for outcomes – and there are always ways that aid could be improved. But at the end of the day, many aid endeavours don’t work as good as you would hope simply because the task at hand is a difficult one. If developing countries were easy places to work they wouldn’t be developing countries.