The pattern of sustainable standard diffusion has received much attention from social science researchers. We contribute to existing literature with a case study on the Rainforest Alliance (RA) initiative in the Ivorian cocoa sector. We scrutinise the RA standard, by drawing on seminal contributions on the pervasive effects of information asymmetry in markets (Akerlof, 1970) and on the inherent uncertainty of credence properties (Darby and Karni, 1973). We examine the uncertainty surrounding standard compliance, in particular the capacity to enforce the standard. We argue that the translation of principles into auditable technical specifications is very rough. Furthermore, our empirical results from producer surveys show that criteria addressing the productivity issue receive more attention than environmental issues. In a context where chocolate companies are extremely interested in ensuring sustainable supplies, we argue that certification, proclaimed to be in the name of sustainability, is mainly perceived as a productivity-enhancing tool.