Saadi Lahlou is Chair in Social Psychology at the London School of Economics and Political Science, in the department of Psychological and Behavioural Science, of which he was formerly Head. Trained initially as a statistician and economist, then a student of Serge Moscovici, he developed methods in large surveys, text mining, participative design and digital ethnography. Lahlou directed the Consumer Research department of the Centre for Lifestyles and Social Policies (Crédoc, Paris), the Laboratory of Design for Cognition at EDF R&D (a whole building instrumented as a living lab), and was a member of the board of the Commissariat Général du Plan (French Prime Minister's office). He has written over 150 papers, books and published reports.