At the end of the day, the great benefit of field experiments to economics and political scientists is that it’s forced some of the best social scientists to try to get complicated things done in unfamiliar places, and deal with all the constraints, bureaucrats, logistics, and impediments to reform you can imagine.
Arguably, the tacit knowledge these academics have developed about development and reform will be more influential to their long run work and world view than the experiments themselves.
That is from Chris Blattman. He concludes:
We are all Albert Hirschman now.