It seems like a no-brainer. Before you spend big bucks on a massive effort to improve life for the world’s poorest — say, distributing millions of free bed nets against malarial mosquitoes, or offering thousands of women microloans as small as $200 to start small businesses — you should run a smaller scale test to make sure the idea actually works. After all, just because a project sounds good in theory doesn’t mean it’s going to pan out in practice.
Or maybe some totally different method wouldn’t achieve better results for less money? For instance, maybe the key to lifting women’s incomes isn’t helping them start a small business but helping them land a salaried job?
Yet for decades, questions like this have been left unanswered.
Instead health and development aid for the world’s poorest has largely been designed based on what seems reasonable, rather than what can be proved with hard evidence.
However, in the early 2000s a growing movement of social science researchers have been pushing policy-makers to do “impact evaluations” of their programs.