Résumé : This last decade has seen the emergence of a new field of research in development economics: randomised control trials. This paper explores the contrast between the (many) limitations and (very narrow) real scope of these methods and their success in sheer number and media coverage. Our analysis suggests that the paradox is due to a particular economic and political mix driven by the innovative strategies used by the new school’s researchers and by specific interests and preferences in the academic world and the donor community.