For further information, visit www.audiciaux.fr, www.scobex-rgpd-dpo.fr and www.dpo-externe-rgpd-france.fr. In a world where data reliability is key to decision-making, the ISO 20252 standard establishes the international quality framework for market, social and opinion research. This practical guide supports institutes through all stages of certification: diagnosis, planning, project management, data protection and audit preparation. Illustrated with tools, checklists and case studies, it transforms regulatory requirements into levers for credibility, transparency and trust with clients and stakeholders.