By describing how consumers are qualified and mobilised in advertising agencies, this paper aims to contribute to this increasing body of literature that explores ordinary marketing and advertising practices, knowledge and devices. This is done by unpacking and analysing a particular aspect of routine advertising work, which is the production and circulation of insights about consumers in advertising agencies. We argue that producing insight involves performing a particular type of qualification of the consumer that relates to two specific processes. Firstly, we describe these practices in terms of an a extensive process of mediation that involves the deployment of progressive definitions of products and consumers that pass by different actors in the agency and through which production and consumption are connected in the very local and specific space of the advertising agency. Secondly, we argue that this process of mediation goes together with a process of ‘purification’ that involves performing a specific version of the consumer aligned with creative advertising work. Furthermore, we describe how this process involves considering some specific consumer qualities and descriptions (mostly interpretations about possible connections between goods and consumers) and leaving others asides. We identify this last operation as a particular type of cultural calculation. This argument is empirically supported by evidence collected from 40 interviews with advertising professionals and ethnographic fieldwork carried out at eight advertising agencies based in Santiago, Chile.