“On balance, the quantitative approach to exploring grand questions about aid effectiveness, which began 40 years ago, was worth trying and may be worth pursuing somewhat further. But the literature will probably continue to disappoint as often as it offers hope. The biggest challenge is to go beyond documenting correlations to demonstrating causation—to show not just that aid went hand-in-hand with economic growth, but caused it. Aid has eradicated diseases, prevented famines, and done many other good things. But given the limited and noisy data available, its effects on growth in particular probably cannot be detected.”
Roodman (2007)