What’s the best way to help poor people: give them food or cash? This kind of socioeconomic question might seem impossible to answer. But thanks to the rise of a new kind of research, one that borrows from the medical sciences, such complex policy questions are being definitively answered. “Randomistas”, as the people who favour this research are sometimes called, use the method of the randomised control trial, in which an intervention is assigned to one of two identical groups to test its effectiveness.
The use of such trials has exploded in the past two decades, measuring everything from the effect of public health measures such as deworming tablets to poverty alleviation schemes such as food subsidies, and now help determine international aid. But are they really the gold standard for evidence? Do they work better for some questions than others? And how can a journalist tell?