Some folks outside Econ, especially in medicine, can't understand why the randomistas won a Nobel. I think this confusion arises because many people mistakenly believe the key ingredient to scientific progress is intelligence. But it isn't: the key ingredient is courage.
It's easy to see that doing randomized experiments could revolutionize our understanding of economic and social policy. But nobody was doing it, so nobody really knew. It was expensive, hugely time-consuming, and extremely risky.
Who had the guts to actually try it? Banerjee, Duflo and Kremer. And what's more they had the tenacity and foresight to pursue a new path and build the social and professional institutions that would allow others to join them if they chose.
This is not to take away from the fact that these three are ferociously intelligent and the randomized trials they designed - as well as their other work - are often extremely clever and go well beyond simple A/B testing.
No matter how good an idea appears in theory, actually deciding to do something when nobody else is doing it takes immense courage. One faces the "unknown unknowns" every day. It takes guts of steel to do this and this is the only way real progress can happen in a field of study.
