Pasi Sahlberg has worked as a school teacher, teacher educator, researcher, and policy advisor in Finland and has studied education systems, analysed education policies, and advised education reforms around the world. In his uLearn18 keynote Pasi describes how learning analytics, algorithms and big data are knocking on the doors of many schools promising fast improvements and new solutions to wicked problems facing schools today. In the midst of datafication Pasi says educators need to remember the power of small data: tiny clues through personal observations, collective human judgment, and raw instinct that can lead to big change in schools. He believes that leading with small data requires collaboration, trust and professionalism as key features of educational change.