Randomised Control Trials (RCTs) have a narrow scope, restricted to basic intervention schemes. Experimental designs also display specific biases and political uses when implemented in the real world. Despite these limitations, the method has been advertised as the gold standard to evaluate development policies. This paper takes a political economy angle to explore this paradox. It argues that the success of RCTs is driven mainly by a new scientific business model based on a mix of simplicity and mathematical rigour, media and donor appeal, and academic and financial returns. This in turn meets current interests and preferences in the academic world and the donor community.